From the tweet you linked:
Even the cops know random damage attributed to #antifa are really "white racially motivated violent extremists...posing as Antifa members."
I don't think I follow what you're saying. People accused of doing something and a false-flag op trying to get people accused of doing something is a distinction without a difference?
I don't see where you're getting "extreme-left white anti-capitalist" from the police description "white racially motivated violent extremists."
'round these parts at least, what they're describing is our local rural and suburban militia-types trying to false-flag violence to kick off what they perceive as an inevitable race war. By their own admission, the people who get caught burning cop cars and such are about as far away from left-wing as you can get.
I took the quote to imply possible categories like copagandists, white supremacists, Nazis, KKK, or even random apolitical opportunists, which is a distinction with a huge difference. After all, Trump did announce something like "Antifa did it" instantly after the riots started while law enforcement across the board has been struggling to find any evidence. It does smell like an astroturfed misinformation campaign intended to drown out criticisms of widespread systemic police brutality.
It is a distinction without a difference.