> I don't see how they have good reason at all.

I believe it's called "intelligence gathering" and "law enforcement". How do you think it works?

Mass surveillance is also called "information gathering" and "law enforcement".

But it's not mass surveillance at all. Specific people, specific circumstances, warrant.

Mass surveillance would be far more likely to find co-conspirators here than an internet thread full of edgelords.

Would you support it in that case?

My argument would be that it isn't nearly specific enough. Simply commenting on a thread shouldn't be enough probable cause.