I don't like the word pretentious. Pretending to be what? What I would agree to is that it isn't as deep as everyone recommending it making it out to be (I'm talking about the original, I haven't played the new version).
Typically people mean something that people engage with it not for its own merit, but to cultivate an image. So, people acting like Stanley Parable is great to look like they have depth of taste because on the surface it's not that great a game.
Of course it could be that you genuinely enjoy artsy comedic narrative games, which I'm sure is usually the case.
Of course it could be that you genuinely enjoy artsy comedic narrative games, which I'm sure is usually the case.