So-bad-it's-good film isn't the worst film in every dimension—often it's competently- or even well-made in at least some ways. Films that are simply all-around bad, made with no amount of skill at the craft and insufficient effort, usually aren't entertaining and aren't the kind of thing anybody wants to watch. So-bad-it's-good is defined by being a kind of bad that one can still appreciate, even if part of the appreciation is of the ways in which it is bad.
There was a thread on here about bad songs the other day, and the kind of bad people meant wasn't, like, an untalented and under-practiced 9-year-old screeching out their original composition on a violin. Obviously that's worse than nearly anything, but nobody means that when they talk about something like "what are the worst songs?" A credible effort has to be put in for anyone to even care to think about it to shit on it.
I think it's still useful to call those categories "bad", even if they're not the most bad. Often the badness is what distinguishes them from the merely forgettable.
I'm reminded also of the corporate art style [https://thebroadsideonline.com/17614/opinion/opinion-the-cor...] - every effort was taken to produce something so inoffensive and average that it could not possibly provoke any emotion in any demographic. Nobody would ever say that this is their favourite art style.
What's your favourite piece within the collections on the MOBA website?
Whatever the people who buy art and are influential say is bad. In general, very wealthy people and the dealers in their orbit determine which art is worthy and which art and artists will be forgotten.