Let me-
                And you're over here stroking your beautiful beard
                Thinking about an obscure quote ethical problem
                The only problem is that you sit around all day and never solve anything
            
Sort of like an honorable mentions section, for people who aren't directly targeted but I dislike nonetheless, namely "thinkers" who just "think" and do nothing else, solving nothing in the end.
                This all is so terrible it's going to make me have a seizure or two
                I am the ultimate machine that will put a grisly end to you
            
Then, it pivots to the perspective of the targets one more time to express their omnidirectional contempt (having a "siezure or two", putting a "grisly end to you").
                Do you see what I see? Smoke in the distance
                A telltale sign of the clash with the resistance
            
I, the criticizer, point out the fighting, the "smoke in the distance". Like in Riot Shield, resisting really means continually fighting, not fighting back against some evil empire in movies and such.
                They're going at each other with rapiers and ballistics
                Neither in the right, narcissists and cannibalistics
            
The pairs "rapiers and ballistics" and "narcissists and cannibalistics" represent the escalation of arguments. Once an argument reaches a certain degree of hostility, neither side is in the right anymore, if either ever was.
                It's best not to get involved, wait until the fight's resolved
                We can never help them because their problems are never solved
            
It's never a good idea to get involved in such hostile arguments, not only because it's no use, but also because you then become a "combatant" and a target to one side or another (or both).
                Back then it was simple but the situation has evolved
                They're too far gone; they will never be absolved
            
Communication has been revolutionized by the internet; so has arguing. The second line is another nail in the "too late for them now" coffin.
                You either chip on fully or not at all
                The bigger they are, the harder they fall
            
In order to join a fray like this one has to fully commit to a view, since every word will be scrutinized by everyone. The bigger you talk, the harder you'll be rebutted.
                (Let them fight)
                Get off of the horizon
            
To my audience - get as far away from these arguments as possible.
                (Let them fight)
                Bleed a bath to cry in
                (Have them brawl to the death)
                The ring, the pit, to die in,
                Yah-
            
About my targets - I've seen and heard about plenty of horrible things said online, some worse than the above.
                (Let them fight)
                Get off of the horizon
            
                (Let them fight)
                Bleed a bath to cry in
                (Watch them try to prevent)
                Their enemies from rising
                Ah-
            
                Do you hear what I hear? Shouts on the periphery
                Efforts to suppress cannot contain those who are slippery
            
I, the criticizer, point out the fighting, this time audible instead of visible, transferring the point of view to actual vocal arguments between people in person. (I know, crazy, right?)
                The rest of the angry mob has equal hostility
                And a bunch of ours are busting out the heavy artillery
            
Now I point out that others are joining the initial two or three, "ours" being theoretical family and/or friends of mine. I say theoretical because most of my family and friends wouldn't actually do this, and this isn't a narrative about me personally. Anyway, "ours" join the fray.
                Of rhymes; and I am not talking figuratively
                Neck and neck and head to head, a brain to mic delivery
                Flawless is my craft, it's all I can do literally;
                If I ever join the fray they killed someone who was close to me
            
The heavy artillery of rhymes relates to "me" (my character in the narrative) finally joining the fray himself. The killing is allegorical just like the rest of the violence in the lyrics; perhaps someone insulted me, or my family, or a friend of mine. It doesn't matter; once it's personal, almost anyone will fight.
                None of them will ever remember what had gone wrong
                The bigger they are, the harder they explode when they're used
                As fuel in the annihilation reaction
                Of an antimatter bomb
            
Sometimes, most of them forget what they were originally talking about. The bigger the group, the harder they blow up in a conflict.
                (Let them fight)
                Get off of the horizon
            
                (Let them fight)
                Bleed a bath to cry in
                (Have them brawl to the death)
                The ring, the pit, to die in,
                Yah-
            
                (Let them fight)
                Get off of the horizon
            
                (Let them fight)
                Bleed a bath to cry in
                (Watch them try to prevent)
                Their enemies from rising
                Ah-
            
They caught each other in the act; I can see right through them
                This is a reference to
                Forgotten
                by
                Linkin Park:
                "Now you got me caught in the act, you bring the thought back,
                tellin' you that I see it right through you"
                I, the criticizer (this is the 3rd time I've called myself that), watched them tear each other down, and I can
                see through all of their fallacies.
            
Seeing's not understanding, what am I to do, then?
Even though I can see through them, I don't understand them.
                You ask me what I think; so you can smell it, too, then
                And now I wonder, (what's it to you, man?!)
            
An ambiguous deuteragonist (one of those theoretical friends or family members) asks me what I think about the scuffle, and I ask in an outburst if he or she is intent on weighing in.
                For the pain
                Both sides to blame
            
There's going to be pain inflicted on both sides by both sides; therefore, both sides are to blame for it. (How eye opening this specific annotation is)
                Fear to lose
                Those such as you
            
Now I'm talking to my deuteragonist (see "You ask me what I think; ..."), saying that the fighters are afraid to lose the people like them, the sympathetic bystanders to one side or the other. Of course, the other side will hate my deuteragonist for his or her sympathy. In this context, I mean almost-support by sympathy.
                Those who fight
                Will justify
                They're in the right
                In their own eyes
            
This is a super obvious one; of course they'll justify their positions, thinking they're each in the right.
                For the pain
                Both sides to blame
            
                Fear to lose
                Those such as you
            
                Those who fight
                Will justify
                They're in the right
                In their own eyes
            
                (Let them fight)
                Get off of the horizon
            
                (Let them fight)
                Bleed a bath to cry in
                (Have them brawl to the death)
                The ring, the pit, to die in,
                Yah-
            
                (Let them fight)
                Get off of the horizon
            
                (Let them fight)
                Bleed a bath to cry in
                (Watch them try to prevent)
                Their enemies from rising
                Ah-