It's the people who don't join in and make their dissaproval of those who do apparant by tutting and loudly moaning that they can't see . .
The show has finished, they're only bowing.
I don't have a problem with people who don't stand up, I get that it's a personal choice, but if other people decide that they do want to then this should be an equaly acceptabe choice.
I agree about standing ovations at the end - sometimes they don't seem very genuine to me but each to their own. However some people do occasionally do it it after songs in the middle of an act, and then it's clearly a 'look at me' moment and damn the people behind me.