I think there is an element of these idiots judging people by their own standards.
They would never go to an event or participate unless they 100% approved of the purity of the organizations and leaders, unless they are writing for the Daily Mail for money.
It does not occur to them that many other people will have a kind of board agreement around an specific issue - two-tier policing is real and bad, say - and will go to events or marches etc about that and don't really care about the organizers or other attendees.
The reason being that they go to represent themselves, they don't see it as giving support to any other ideas other have, be they organizers or whatever.
But then - they are not consistent - none of them seemed to think we should judge the people at BLM rallies by the problems of the leaders, who were grifters and racists. Which is correct - most people who went to the rallies didn't care much about the leaders, they were there to make a statement on their own behalf.