The only reason it seems wrong is because we have been told growing up that meaningless sex is bad and that sex should be special. Had we grown up in a society where it was frowned upon to only have sex with those you love, meaningless sex would be the most awesome thing in the world.
I'm not saying sex with a partner isn't great/different. Of course there is a connection that you can't find with a stranger. However, there are awesome things you can't really do with a partner (most of the time) but can easily get away with while having sex with a stranger. By awesome things I mean being really rough, filthy, and not having to have to respect the one you are having sex with. I don't mean beating the shit of of a stranger while having sex, or anything anything along the lines ofnrape, I don't mean it like that.. I could never imagine getting violent (playfully) with my girlfriend, but with a stranger... hell yeah. I know not everyone is into that kind of thing, but kinda like it.