I dunno. It depends. Many clop pictures are simply ponies with visible genitals. Nothing special, simply anatomically correct art, maybe a bit suggestive. But some clop crosses many lines at once. Pedophilia, incest, rape, add some tentacles, futanari, body with weird proportions, borderline bestiality, vore, and other weird Japanese stuff… Personally, I think gore is not as disturbing as some of this stuff combined.

To me, there's a limit for both. I will say, however, that I am a bit more averse to the idea of gore.