I'm not going to argue with you on Antifa and BLM, as that is a separate issue.
What the FBI is angry about though, is that a federal officer was brutally murdered. His head was caved in by a fire extinguisher and then his body was thrown to rioters, who beat and trampled him, even going so far as to use the American flag as one of their instruments. They've taken it personally and because those same rioters were also networked through multiple sites where they planned attacks, riots, and assassinations of President Biden, the FBI has a treasure trove of information on them and anyone associated with them.
And Parler just twice fucked them, as all those idiots put on their own personal information. Hell, Parler was nuked impart because of its association to those protests and riots. And right now, those same QAnon crowd are facing wholesale bans on various secondary sites as they try to find a place to host them.