Don't listen to the reviews for the movie.
Almost every person who gave it a 1-star review was just complaining about the literal two second scene that had a same-sex kiss, and didn't give any actual criticism about the movie itself.
Lightyear was a really good movie, right down to the jokes, plot, and even the pretty clever twist towards the end. (Not going to spoil what it was, you'll just have to see it for yourself.)
Even if it goes against your beliefs, you should give the movie at least a chance. You might end up actually enjoying it.