A decade ago the FBI heavily shifted its focus to CVE, countering violent extremism. At that time, the focus was on Muslims and groups that could be perceived as proxies for their interests (Anti-War protesters, pro-Palestinian groups). CVE relies on debunked theories about radicalization, and its definition of violent extremism includes peaceful, constitutionally-protected, political speech.

More recently, focus narrowed from violent extremism to RMVE, racially-motivated violent extremism, focusing on white supremacist groups--the definition of "white supremacist" being interpreted so broadly as to include explicitly anti-racist libertarian groups.

Given that the FBI officially considers "violent extremism" something to be extirpated, and defines it so broadly that the majority of the activity falling under that umbrella is legal political activity, I don't really see how you can possibly make the case that the FBI isn't trying to quash dissent. FBI raids have a chilling effect on political activity, they know this, and they use it.