What's with all the hate towards trashy/vulgar humor these days?

Funny is whatever makes us laugh, no matter how childish or vulgar it's perceived to be. And why do we need a solid plot in a comedy, why is that so important? The Brothers Grimsby and Vacation were two films that were brutally trashed by critics and audiences this year for being too crude or vulgar, yet I was pleasantly surprised by how funny both films were. These aren't bad movies. IMO they both had some really good comedy writing behind them.

I really don't understand this current cultural zeitgeist we're experiencing. It's as if everyone's waiting in line to get their membership approved at the country club, and we live in the most prudish society.