But those movies aren't piles of shit then, because they achieve exactly what they set out to do. An actually bad movie fails to achieve that.
If I think a movie is actually a bad movie that usually means it's boring to me. Like, Aliens v Predator, or (Emmerich) Godzilla or the Schumacher Batman movies. Why would I re-watch something that bores me?
But I think it goes back more to what we mentioned with music: "guilty" pleasures aren't really about the movie itself, the feeling of guilt is more about liking something that you know you're not supposed to like - and there can be reasons other than (perceived) quality for that. Movies have target audiences, and being in the wrong one and still liking it can mean you feel guilty about that. And movies also project a certain image, and maybe you don't want to be tied to that. (Humour in movies and TV shows is sometimes derived, for example, from tough guys liking Titanic or something.)
Say, there are movies that I think are really bad that everybody else thinks are great*. In the same way, say you're a New York intellectual in a Woody Allen-esque circle (if there actually is such a thing, but you know what I mean), you know you're not supposed to like stuff like the Fast and Furious movies, so watching them would be a guilty pleasure. Or if you're a motorcycle gang member (Sons of Anarchy style) and you love Les Miserables and rewatch it every day, that'd be a guilty pleasure.
So, I guess, on a forum like this, Batman v Superman could be a guilty pleasure to someone (if opinions were more uniform than they are here, where a significant amount of people will cheerfully admit to liking it)