The Tea Party co-opting was really frustrating to watch and also really frustrating how easy it was. That seems to be a problem with almost all movements though. There is a tendency for people to just go along with increasing degrees of violence and stepping well beyond the initial message they were trying to make. It is a psychological trait of humans and mob rule tends to take over and minimize most voices.
The BLM movement is rooted in a solid message of dealing with the egregious personal violations that continue to happen at the hands of the state. But if that was the only message than I think it would be a lot harder to co-opt. It seems the purpose keeps getting muddier as time goes by.
"Black Lives Matter" Yup.
"Protest in the streets!" OK.
"Arson and vandalism!" Wait, no, that's counterproductive.
"Defund the Police!" Sounds good.
"Tear down statues of confederates!" OK. Seems a bit off-topic when addressing current events, but whatever.
"Well, don't really defund the police, but instead set up a whole new bureaucracy! And trust government again!" No, you've lost the plot.
I find it odd that people scream to gt rid of the systems and then they go and enact ones even more barbaric and orwelian that completely negates the entire point of the movement.
"The selfsame system that created our present problem of corrupt cops, abusive courts, byzantine laws, unjust wars, corporate collusion, an epidemic of regulatory red tape, and immigrant imprisonment needs to run health care and send social workers everywhere. There's no way it can go wrong if we add even more layers of bureaucracy! Also, you owe us more money, you greedy bastards!"
Bureaucrats will bureaucrat. That's why the allegory of "the first to go were the lawyers and politicians" very well may come true.