FWIW, there's plenty of alt-right "advice" out there to use left wing messaging if someone decides to do something stupid. It's potentially a tactic to misdirect and frame the violence.

Not really, the "hey fascist, catch" one is from helldiver's 2, where the satirical fascist human soldiers ironically call the bug aliens they fight fascists. The arrows are the code to call in an airstrike.

This dude was putting his groyper memes on his bullets

casings can very easily be planted. that shouldn't be convincing taken on its own.