Marek, I'm definitely no sharpening guru and although I have an interest in steel metallurgy, I'm not an expert in that either. My understanding is that carbide pull-out is microchipping caused by carbides being pulled out during use. It's more likely in highly alloyed steels with large carbides (I'm guessing tool steels including PM steels and many alloyed SS are in this category). It's more likely if the angle at the very edge is greater than that particular alloy can support. For example, I have been told that 14dps is far too acute for SG2 (which is hardly the most alloyed PM steel). Carbon steels and fine-grained SS with fine carbides (such as AEB-L) don't tend to have this problem, even with very acute edges. Microvbevelling is often suggested to counteract this problem.
I'm not sure the extent to which this is based in theory vs empirical evidence, but some guys who seem to have a lot of sharpening experience place a lot of store in it, so I guess that it's based in their experience, at least.
I'd very much welcome the input and perspective of those who know more.