[Note. This list should become a list of seven, to celebrate Goodman’s Seven Strictures on Similarity]
Speaking for myself, I’d rather have no labels at all. But I try to stay realist about using labels ;-) So you’re question is an important one. Here are personal strictures I employ.
A first stricture would be to use labels proponents themselves use. To that effect, “contrarian” fits the bill. Steve uses it, so it’s good enough for me. 
A second stricture would be to always describe what one is talking about. If I say that when I refer to realism, I am speaking about the belief in abstract objects, the readers may have a better idea as to what I have in mind. This is a basic methodological point.
A third stricture would be to minimize the use of these labels Even properly identifying a thesis can lead readers astray if all the sentences contain a mouthful of predefined terms. It’s really tough to follow discussions that throws around words like “realism”, “socialism”, and “activism”, even when they are well-defined in the context where they are used.
A fourth stricture would be to use the objective form, not to get too personal. It’s better to talk about realism, socialism and activism than realists, socialists, and activists. Note the important difference between “denier” and “denial”. So “catastrophism” is better than “catastrophists”.
That said, I do not believe that labels are derogatory in themselves. It is possible that catastrophism becomes accepted by catastrophists themselves, like Solomon did with his book The Deniers. All really amounts to what is tolerated in the community. A community that tolerates expressions like “tribalism”, “cargo-cult” and “drinking Kool-aid” might have a skin tough enough not to get all outraged by “denier”.
My original point was only about the second stricture: identifying what one is talking about. It was not about using labels as such. I will excuse myself with the lame “Tom Fuller Made Me Do It”. ;–)
 Steve does not use the term for himself. I disagree. My point here is to underline that it’s a label Steve uses.