Why do people dislike/struggle with uvhm?

I've seen quite a few posts about people talking about how uvhm is too hard or not fun etc. I really don't get it, uvhm was a slight step up and extremely fun. I blazed through it on my first ever playthrough as a pretty crappy melee zero. Not trying to be rude just genuinely curious. Anyone with an opinion like that care to explain where they are coming from?