It's a matter of opinion, and only opinion.

Art is subjective in nature, so you can't really quantify it as good or bad. Even if a song doesn't sound good to one person, another person may think it's the best thing since sliced bread. Because it's subjective, one can not simply state their own or even others, even if they are highly renown critics, as facts. Even if we had created a computer AI in order to judge such a quality, I don't think that even a computer has the power to analyze a piece of music and determine if it's good or bad.

Sure, artists can be bad. But music itself?

There's plenty of reasons to dislike a song, and there's ways that songs can be morally bad or created for a sinister reason. There's songs with dubious morality, such as songs made simply as a product to sell. Examples of these would be influencers who go into music simply for a product to sell, such as the popular Dixie D'Amelio making her music, or the rapper Bhad Barbie who profited off of her fame. Music made by rapists, abusers or etc, of course you can disagree and dislike artists for their decisions in life. Everyone gets to have an opinion.

What I'm referring to are subjective opinions on music quality, excluding extreme cases of moral questionability. Is the music industry problematic? Yes, sometimes. Do morally bad people get fame and fortune because they're lucky? Yes. But can someone make a timeless, unmovable decision about the equality of one piece of music? I don't think so. No one can have bad music taste, even if they really do like lifeless money grabbing products.

Music can be off beat, out of tune, and have dissonant sounds. But some people could still like it. 

Of course, music can have sounds that hurt our ears, or just subjectively sounds bad to the ears. This is absolutely valid. But if someone happens to like that kind of music, I ask everyone to stop making fun of what other people like. Not in a "this is my bets friend and I'm joking way" but in a "I'm fighting on twitter with strangers" way. Arguing about music, or any art in general is counter intuitive. No matter what kind of music, someone at least some person out there will like it.