Projecting your other stresses onto RPGs and the other fans probably isn't a constructive coping strategy.
Sure, but I also don't think that's what the OP is talking about given his examples, which seem more about people just holding
themselves back because they think it's "embarrassing" to like something, or because they feel they need to recognise the illusionism rather than embracing it, or because they're being almost consciously cynical and preventing themselves enjoying something by essentially "being in their heads", rather than projecting anything.
Also, re: projecting stresses, I don't think that usually changes whether something is seen as flawed or not, at least in my experience, just sometimes (not always), how severe that flaw is seen as being. Further I think being angry and/or in pain rather than stressed or anxious is what tends to provoke the most negative reads of RPGs, of media, of theme park experiences, and so on (aside from a generally OTT writing style). I immediately think of a couple of times where people I know IRL had really like, shockingly negative takes on a movie that was like, uncontroversially good, and where it turned out both were really sick and in a lot of pain when they saw it, and rewatching it later had distinctly different experiences. Whereas being stressed - in my experience -tends to just drain any ability to enjoy something or even engage with it, so rather than having loud criticisms, you tend to have nothing. Unless the thing is
so immersive it manages to make you forget your stresses and so on!
I think this is important to discuss because people are fairly routinely criticised in fandom and less routinely in life for failing to "embrace joy" or the like, and I genuinely think the reasons the OP presents, whilst real (I've seen them myself), are kind of in the "first world problems" zone of "failing to embrace joy". Perhaps cynicism is the worst of those by a fair margin, because that can be very hard to shake if it's deep to someone's persona.