People don't actually like rng, no matter what they tell you. That's why strategies used mitigate it and eliminate it as much as possible. This isn't a new concept, just look at crafting rotations. It's way more palatable to die and know it's your fault, because you can look at that and be like, okay here's what I can do for next time. Feeling you lost because of a dice roll isn't fun, satisfying, vindicating whatever. It feels like BS. Likewise there's little sense of accomplishment winning in a situation because you feel like you just got lucky, there wasn't any skill involved. The world first races, which believe it or not a lot of people do care about, would be a lot less meaningful if fights were heavily rng reliant.

To their credit, the devs do a good job of keeping it interesting. Adding randomness to the mechanic itself adds a deep layer of personal responsibility without tipping the scale into unfair. Stuff like the random queen's waltzes, the library phase, exdeath's black holes and emptiness patterns are just a few examples of this.

Anyway, if the fights weren't hard, then anybody could do them, but people still struggle with halicarnassus much less exdeath, and ultimate coil has still only been cleared by a couple tens of people, and it's not for lack of people trying.