It depends a little bit on how you define 'bad' and 'good'. Music can be objectively well or poorly executed. Although intentionally sloppy or unusual music can arguably be good in part because it is technically 'bad'.
Music can be made with a certain purpose in mind such as evoking certain emotions. Some music can be bad at making you feel a certain way, some can be good.
This would require a definition of what makes music "good" or "bad". It may be that music that is accepted as good by a majority of the population is "good". However, baroque composers will take umbrage at that statement.