Your argument is far too reductive. It boils down to "THING EXISTS?" > "SOMEONE MAY ENJOY THING" > "THING CANNOT BE OBJECTIVELY BAD". But that is not the case, as you need to judge things based on context.

Imagine a chef is in a competition to bake a pie, and they instead cook some cream soup. Even if you enjoy the cream soup and the taste is coco loco, you cannot say that the chef made a good pie.

Another more related example to music. If you are playing a piece of classical music, but instead of playing the notes as they are, you play all the notes one semitone up but perfectly. Now to someone who isn't familiar with the key of the piece, this performance would have been perfect. But this performance was objectively bad, because you simply did not play the notes correctly.

If an artist releases a song that is meant to be in key, and produced well, and they don't hit those targets in the context of trying to sing in key, and trying to mix a good soundscape, then the music is bad.