Oxygen doesn't positively effect everything it interacts with. Therefore, it isn't only good. Oxygen can be very bad for a few things in my line of work. It also oxidizes things which is sometimes not good.
Religions are fictional.
That would be something bad about herpes, or the girl.
Regardless of your views on religion, they do establish certain ethical rules. If a religion says oral sex is bad, then it's bad. This ties in to my original point that good and bad are human creations.