It's not weird by any means. I worked as an usher for a little while in a very popular cinema complex and you wouldn't believe how many people go to the movies on their own. The one kid that gets dropped off by his mom. The one dude that's on his own, the one girl that's on her own (some of them pretend they're waiting for someone and fidget with their phones). Lots and lots of old people - mostly women - who go on their own as well, as part of some sort of ritual, to see every movie they're showing, just because.
I've also worked as a movie critic for the past 4 years. I go to the movies about 70 times every year, and most of those times (like 60) I'm on my own, on assignment, at a press screening. It's not the same as regular movie-going since - as much as I fucking love watching movies for free - it's still a job, and the room is filled with people who are "on their own". Hell, you get to recognize most of them. And you're working, technically. So no stigma there.
I'd have to say it took me a lot of press screenings before I decided going on your own to the movies wasn't bad at all, and I've gone to the movie theater on my own since then, when I'm bored and it's nearby or it's one of those movie cycles of some sort (I watched like 20 Federico Fellini movies in 2 weeks, mostly on my own, and I had a blast doing that).
So to answer your question - it's not odd on account of the fact that a LOT of people do it, for a LOT of different reasons and in a LOT of different contexts. There's nothing inherently extraneous about that.