Please show me any evidence that BLM were calling for violence against people.
I don't know if you're gaslighting here or just not understanding the situation to compare it adequately, but 1) the BLM protests were separate from the relatively few who rioted, and 2) your comparison to think a growing amount of Trump's supporters openly calling for violence - and then attempting a coup to takeover the Capitol - are the same, then you're not a reasonable person; it's an apple to oranges comparison, not the same at all if you're actually critical and differentiating the situations fully.
Calls for violence are, what private platforms are determining on their own, not okay. The government is the one who shouldn't have the ability to say what is and isn't okay, and the government isn't preventing people, nor is the government arresting people for calls of violence - they are arresting people for violence or trespassing though - like at the Capitol; you're wanting to give this power to government to say what is and isn't okay to say - which is a mechanism tyrants need to succeed.
ISPs et al already are blocking or actively trying to filter for content like child abuse content - or do you feel such content should be freely allowed to be spread? Facebook et al are moderating to remove such content too.
Maybe you draw the line at pedophilia and child abuse photos but you're okay with people inciting violence? These platforms have drawn the line at people inciting violence - and not even that, but that moderators of these platforms were allowing it to stay on and not deleting. If Parler for example was actively and adequately removing such comments by their users, then these platforms wouldn't have deplatformed them.
Civil society is a thing you work for, you don't get there by letting people do whatever the fuck they want - just like if you're a parent you don't let children do whatever they want.