Good one! I've had the same thought for a while and wanted to meme it, but just couldn't but it together succinctly.
A prime example of what you're talking about is "Archer", one of my favorite shows. It always starts with the rating warning MLSV or whatever it is, complete with a voice over stating that it is intended "for mature audiences" and all I can think is that the humor is really IMMATURE. Hilarious, yes, but immature.