I think GP is going too far in calling you a liar, but I think for the most part your FSD praise is just kinda... unimportant and irrelevant. GP's aggressive attitude notwithstanding, I think most reasonable people will agree that FSD handles a lot of situations really well, and believe that some people have travel routes where FSD
always handles things well.
But ok, great, so what? If that wasn't the case, FSD would be an unmitigated disaster with a body count in the tens of thousands. So in a comment thread about someone talking about the problems and unsafe behavior they've seen, a "well it works for me" reply is just annoying noise, and doesn't really add anything to the discussion.