You're asking that on a story specifically describing how the FBI is either avoiding or directly violating the constitutional restrictions they are supposed to follow?
I'm sorry, how did the FBI violate anyone's First Amendment rights here? Where in this story did they take down content? Where did they compel speech or silence or association?
LMAO you do not have a first amendment right to not be investigated for making threats in public, even if those threats are baseless! You do not have a right to baselessly threaten people!
Their agents were bypassing OP's security measures (and breaking the CFAA) to make an extremely broad search of their papers. That's absolutely a Fourth Amendment violation.