but what baffles me is how they end up locating this forum to post about 1xbit scamming them after they've been scammed.
It's pretty simple actually. The first thing that any victim would do when they get scammed is to search for '1xbit scam' or anything similar on google and the first page displays results like Trustpilot, Bitcointalk etc.
This is how they find about this forum and create an account here with the hope of trying to recover their lost funds basically.