I've heard this argument several times.

It's important to note that an enormous amount of humiliation play involves berating the submissive for things that are not actually shameful but are often shamed by society. It's not shameful to have a foot fetish or a small penis and yet we release all kinds of cruelty upon our pin-dicked little footfreaks. The point isn't that those things are bad -- the point is that it's hot (and sometimes very cathartic) to hit the sexy shame button repeatedly.

I find it much grosser to humiliate a submissive over things that are actually shameful. He's turning his genuine wrongdoing into a sexy game and asking me to enable him.