People with no sense of musicality like bad music because they don't understand what makes music good. People who are afraid to be different or want to fit in with their friends like bad music to be accepted. People who think a band is just too cool on stage like bad music because... the band looks cool on stage. There's tons of reasons why people like bad music. Still doesn't make it a valid opinion to call it good.
No. No one can simply declare that a work in good or bad simply based on their own criticisms, as much as people want to think they can. There's always a large of number of different factors in play. Look at cultural biases. Different countries have different histories and tastes, which can vastly affect how the quality of a work is viewed by that country. You can't say that some music is objectively bad, because the appreciation of certain kinds of musical styles are steeped in the biases and influences of every person. Only if it completely fails to garner any kind of acclaim, usually because it fails to deliver anything close to what it was supposed to be, can it be considered bad.
In the end, it's entertainment. People wouldn't like it if it wasn't entertaining on some small level, which means it's doing its job, which means it's good. We all have our "guilty pleasures", things we enjoy even though we know it's shallow or unambitious, but where does that foolish mindset come from? Obviously, if we like the work in question, even "guiltily", then it's doing something worth admiring. It shows quality, even in an area we try not to give credit to. It's good, plain and simple. No matter what one critic may think about it, a good work will prove itself. A bad work will fail into obscurity, like it's supposed to.
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Okay, I rolled a 14. What's that mean? Hsu
That you're a cheater. This is a 12-sided die. Chan