I really don't get the stigma...you're in a dark place where you should be quiet. Sounds almost like a library.
I used to go quite often, but since I live with my girlfriend, the only time I go to the movies is gonna be with her.
There's generally stigma about doing literally anything in public on your own. Going to movies, going to a restaurant, traveling, etc etc.
Society as a whole has a hard time grasping that sometimes people don't want to deal with other people, but they also don't want to stay at home with the blinds closed and the lights off. It's a shame really.
---Assassins do it from behind.