Noone is criticizing social/ generalized anxiety. It's the poor taste in humor (rubik's cube for long cutscenes, F'ing babies, rape/ consent jokes, being a dragon, etc). The runner got a lot better after a half an hour or so but it wasn't just Gaf saying this. The chat was rife with those comments too. The runner is a streamer themself and as of right now it's clear that they are doing fine in front of the camera. It was just a very poor choice of words earlier on that people reacted in kind to.
That said yeah the run got a hell of a lot better once the prepared jokes were exhausted.