Approach.
I think most of us have dealt with at least one sh*thead player, and it's natural for us humans to get a little hung up on a single bad experience.
I think, too, that most importantly, it's just people not knowing how to give or take criticism at all.
So, a bit of special snowflake and just trying to help rolled into one bad package. You find players who feel they are doing great, and the moment someone attempts to broach the subject of improvement, it feels like an insult, when 99.9% of tge time it's just genuinely trying to help a friend out.