The anger of the oppressed is understandable if not always justified in it's expression. The violence of their oppressors is only justified by OVERT RACISTS and FASCISTS - such as yourself. Decent people either oppose it - or just look away and pretend it doesn't exist... Or they cling to the flimsiest of justifications - offered in its excuse.
BLM has no control of what someone yells (or in reality DOESN'T) at a march. The movement against UNACCOUNTABLE POLICE MURDER and white supremacy has existed much longer than BLM - and I see nothing in it that comports with your evidenceless assertions. In any event that is NOT the platform of the BLM group. October 22nd Coalition/STOLEN LIVES project doesn't endorse killing police either. They simply demand justice and accountability.
Antifa is NOT a monolith. There is no corresponding source of funding and organization, as the far right has in Robert Mercer, the ODESSA NETWORK and Koch Brothers money, and media.
The flag of antifascists is used by many groups - who ALL rightly oppose fascism. Some are Communists, others are anarchists... Some are Democrats and Republicans. Some are Punk-Rockers like (Green Party) Jello Biafra. It is a very old cause. Not all supporters are inpolitical agreement beyond their opposition to racism and fascists.
So yes. I am an ANTI-FASCIST. I have been for several decades. I have researched and broadcasted on these topics.
You appear to "broadcast" without any (legitimate) research. Or you're an overt racist and fascist supporter with an oppositional-defiant relationship to the truth... I wonder which one it is?