Democrap and the like are simply derogatory terms. And so are abbreviations like M$ for Microsoft or the German term Windoof (could be translated as Windumb) for Windows. But this is not the kind of terms Stallman uses.

Instead, he usually tells you why he uses a specific term and I have yet to come across a case where he doesn't have a point with his term. Microsoft can be regarded as „Malware“, because it does things you do not expect and may not want it to do (like spy on you). Facebook users can be regarded as used, even though I don't think there is any point in denying that they themselves use Facebook, as well. I'm not educated enough to talk about DRM, but it seems he has a point in calling it Digital Restrictions Management, too.

If I'm not mistaken, Stallman now actually prefers the term libre to the term free, because it is less ambiguous. Or he sees the value in it; I don't recall it exactly.