Or, of course, both, since the feds love to let these things happen. I'm thinking very high chance of some level of leftist network

That is what I think happened. Who would be surprised if the CIA or FBI has been radicalizing young men using antifa and the left as cover?

On a side note, white men are the ones that commit this (eg. Trump's assassin) because the ethnic minorities in this groups are in it for themselves, they're pragmatic. White men that fall for this are ideologically brainwashed.