I don't think I've ever used the Alt-F4 line, but it is possible. I have a theory on it.
There was a time when being online, being in an online community, and playing games online in that community took a predefined level of skill. There was an intellectual prerequisite that meant you earned your place to be there. You were technically savvy enough to do this, so you belonged. Things changed. Partly Microsoft and Apple's fault for making getting online so idiot-proof.
I don't see the Alt-F4 as a 2nd grade humor. I don't see it as children repeating it. It's old-school. The older folks are doing it and perpetuating it. It stems from a time when you had to actually know how to dial in with a modem or fill-in-the-blank. Now every foul-mouthed 8-year-old with an ego complex is filling the game and forums, I see the Alt-F4 resurgence as a reaction to this. I see it as... possibly... a way of getting back at those that don't belong. Perhaps there's an element of elitism in there. Perhaps it's also about retaining the "good old times"... And perhaps it's also about teaching these young people they don't know it all and that maybe there's a lot they have yet to learn.
I think all of those combined play a major part.
At least, that's my pet theory.