A safe movie

It's not a bad movie, not a good movie... it's just a mediocre movie.
It's like the writer were afraid of offending someone with the jokes, so the writers opted for safe jokes.
Even the more "edgy" jokes like when Karen says "cancer is sexy" (or something like that) they feel the need to deliver an excuse, so Gretchen tells Karen "no, you can't say that" or when Kevin G is rapping and the teacher tells him: "that's inappropriate", I mean, we know that singing something like that is inappropriate but why this need to "apologize"???