I think you're exactly right - based on everything I've read and experienced. Most organized harassment is perpetrated by civilians with the tacit approval of the local and federal cops - which makes it less likely that anything ever gets exposed or leads to exposure of gov't involvement. And as you suggest, hackers and others don't play by rules (warrants and such).<quoted text>
There are tons of government contractors as well who are hired in part because they don't have to follow laws. Snowden says they have access to tapping anyone's phone lines that they want, if they choose to. What are the chances that they won't? They are right out of school and are making gobs of money and probably never leave their computer monitors. They really could start setting up all these mind hacking and social engineering games and they probably do.
The only time warrants are needed are when the gov't is seeking to prosecute someone - so they need legally obtained evidence. For stalking and harassing someone, that's not an issue.