They're all synonyms with very little difference in meaning. "to humiliate", though, implies that you're demeaning/debasing/belittling/etc. someone in the presence of others (but that's not always the case). It also happens to be the "strongest" and most common of the words listed, in my opinion.

"to disdain" and "to derogate" aren't commonly used. I see and hear "to disparage", "to belittle", "to demean", and "to degrade" mostly on television news casts, documentaries, newspaper articles, and novels, and other such high-diction mediums.