Exactly why I've always felt that giving a facial is one of the most degrading things you can do to somebody. When you pump a batch of baby batter onto someone's face, not only does he/she look owned, but he/she metaphorically is owned...It's absolutely one of the nastiest, most humiliating, and degrading ways of signifying that you've just conqured that person
I think a lot of people would agree with you, and that sense of domination and or humiliation/degradation (depending which side you're on) is exactly what turns some people on about it.
Me, I never understood that point of view. I never thought there was anything humiliating about getting a facial. If I'm trying to get a guy off, it's because I'm attracted to him--maybe I even love him--and it's fun for me to get to play with his body. Getting a load in the face is like a reward or trophy for a job well done. If you want to analyze the power dynamics, then if anything I have power over him. After all, he has yield to my touch and allowed me to manipulate his body (and mind) in ways that are out of his control. When he cums he's giving me his power, his energy, expelling a portion of his very life essence, and it's mine, all mine!
If you want to bring religious metaphors into it, one could look at it as a sort of baptism (and swallowing as communion).
From a negative angle, it's also like a kind of vampirism.