Begging your pardon, but: UI design has plenty of research to show there’s some objectivity in it. Human perception is a thing with a lot of study. Just because an uninformed user can not perceive that things could be easier on them (with a better design that they don’t actually have available to them for comparison’s sake) does not mean there aren’t objectively better designs that WOULD make things easier for them.
I’ve spent most of my life watching users be blamed for (and blame themselves for) problems that come down to software (and hardware) being poorly designed. Users who aren’t informed about UI/UX design and human-machine interfacing/psychology/perception will simply presume that things are as good as they can be (putting the designers on a pedestal, out of naivety) and will believe that they themselves are in the wrong, when they’re actually being fairly reasonable from a human cognition, behavioral, and cultural perspective.
When I was last in tech jobs, I made it my thing to be the opposite of the elitist tech geeks who are happy to promote “the user is the problem” attitudes that keep uninformed users feeling intimidated and ignorant.