Whether you call it being fashionable or cool or modern, considering that when appreciating anything is dumbfuckery. It may be the opposite of only admiring things that are old and traditional or whatever, but it's the same mistake, just done backwards. And inability to react to something unfamiliar with anything except mockery is the kind of laughter that invariably signals a fool. The guys in the theater were put upon by some dipshits and got pissed off in a blog. What's the big fucking deal?
I think the sharp reaction has to do with the unvoiced belieft that opinions are equal but people aren't. The people watching Singing in the Rain apparently didn't bother to watch the movie but watched each other play the fool. Getting called on it was mildly unpleasant I imagine but the overreaction to the initial blog post strongly suggests that the old fuck wasn't supposed to step above his station. Expecting that people would have the elementary sense to leave the Bond movie if they couldn't get into the movie again was some old fucks insulting their betters for their opinions.
Nobody has been retrained to appreciate the trope by Glee. Glee was merely acceptable because it had acceptably youthful faces and comfortably familiar surroundings. Not getting into Singing in the Rain is one thing, but making no attempt to watch the movie was refusing to do the assignment. Not getting into Bond is a difference of artistic opinion, but deliberate rudeness is not. And deliberate rudeness over something so trivial really is about as unsophisticated as you can get.
The supposed objection being that esthetic standards are used as markers of elite status in the context of the original blog post is a commonplace fake populist swindle. Or, possibly, you might have to use populist in its negative sense. After all, rejecting a movie because it's old is awfully close to rejecting it because it's black or foreign.