I’ve ran into a few and don’t know how to report them.
Report them in game or report their profile
If I remember right there’s 2 ways1) In the CS GO game, press Tab while playing and go to the person that you want to report and press Enter. Then click Report and go from there.2) Load Steam. Click View (at the top), and click Players. Look for the person/people that you want to report and click Profile (beside their name(s)). Then you will go to their profile and you can report them by clicking Report Violation (on the right) and going from there.