Well, you can "objectively" compare bands on a technical level, but that doesn't necessarily mean that one band is better than another.

In my case, I do feel there are things that some bands do better than others that makes me want to applaud them for trying to go the extra mile, but as not everyone cares about that kind of thing, my opinion is therefore subjective.

If you want to apply objectivity in music, than pick something more specific in music to do the whole compare/contrast thing instead of trying to be unnecessarily broad and binary.

if a specific piece of music had objective qualities with regards to its quality, it does not follow that there would be equal lovers and haters. objectively good music would have more lovers. it's pretty straightforward.

of course, nothing has objective qualities. the properties of things in the world subsist between subject and object, and only arise out of interaction between the two. after all, music would be nothing more than fluctuations in air pressure if there were no ears for it to fall upon...