I think we should stop arguing this point - he’s using a wholly different definition of “assault rifle” to the rest of the world.
According to his terminology, the M1 carbine /is/ an assault rifle, the M16 isn’t (despite the rest of the world thinking it is), and the XM8 is an SMG (despite it clearly being an assault rifle, since it fires rifle & not pistol ammo). He also said at one point that the Stg44 is an SMG. And an assault rifle, according to him, is just a rifle used in an attack, which must have a carbine length barrel. He’s also invented the term “defensive rifle” in a military context, which a rifle magically turns into when used defensively.
So, unless he agrees to use at least a similar definition to the accepted standards, and stops using his own unique pants definition, it’s clear that he’s just trolling & is getting kicks from it.