Mostly because with the MPAA, a movie can show fellatio and still get an R rating, but if a movie shows cunnilingus, there's more of a risk of the movie being rated NC-17. At the same time, I don't know a lot about the subject of oral sex and double standards, so I could probably use some enlightening. And sometimes, it seems like American society is more comfortable with fellatio than cunnilingus, but I could be wrong.

Yes definitelly, because fellatio is considered something normal and expected from every single woman, and yet cunnilingus is frowned upon and considered disgusting, it's horrible that these days women are always pressured to blow guys and yet they aren't even bothered to retribute the favour.