I think you're being downvoted because there is an ambiguity in what "subjective" refers to here. The core criteria of good UX are not subjective, as you say. B

I think you're being downvoted because there is an ambiguity in what "subjective" refers to here. The core criteria of good UX are not subjective, as you say. But whether a certain UX qualifies as good under those criteria depends highly on the audience. A good video-editing UX for amateurs looks completely different from a good video-editing UX for professionals. Long-time users of vim or emacs love their editors because of their UX, while many new users hate them for the same UX.