I really don't see evidence for the existence of OMV to be better than for the existence of OMT. We can't use nonexistent thing to prove the existence of something.

1. Is it true, people differe significantly on what they'd classify as good in terms of morality or music?

YES. Our disagreement starts at very trivial issues like is it morally good to cheat during some exams, through whether killing animals is good or not, then whether it's good or evil to tax people, decline refugees, to things like "is it moral to torture people as a form of punishment or in order to get important information" or even extremes like whether killing other people is bad or not.  There is no agreement whatsoever. In case of music it's obvious too.

2. Are some values/music genres shared more commonly than others?

YES. It's quite common not to torture animals, and it's quite common to listen to pop hence the name.

3. Are some values/music genres peculiar to some lesser comunities based on nationality, culture, tradition, etc?

YES. You're more likely to like gospel music if you live in USA, and more likely to think it's morally ok to eat dog if you live in China or morally ok to kill other people if you live in ISIS.

4. Do people change their moral codex/music taste?

YES. One can strongly believe homosexuality is evil only to completely change his mind later on. One can also love pop and switch to classical music after some time.

Some people try to smuggle OMV as properly based belief. I don't see how anybody in their right mind could say it's properly based. To me it's as much properly based belief, as belief that Objective Music Taste exist.  We don't agree on what is moral and what isn't, we don't agree whether OMV even exist, we have perfectly sound naturalistic explonation for why we care about so called morality and why we seek for some objectivism, there is no practical necessity to assume the existence of OMV as it is in the case of other beliefs like belie f in reliability of reason, logic, existence of the external world, etc.

And to makes matter worse not only existence of OMV isn't supported by any sort of evidence or reason, it also doesn't prove the existence of any god! Let alone good god.

First of all, why does the existence og OMV require god in the first place? I didn't see any explonation for this. Why OMV simply can't exist? Like laws of nature may not be prescriptive but only descriptive, we can apply the same to OMV. So again, why is any further foundation required?

Second of all, even if god exists I don't understand how it necessarily has anything to do with good. I think we have three scenarios here:

1. God does things that are good, because good knows what is good. It implies good exist beyond god, that means we either need greater god, or accept that OMV simply exist.
2. God does good things because god is good itself. Since god doesn't require any further foundation or creator and god is good it means good doesn't require any too. Also let good be good and god god.
3. Something is good because god said/did so. It makes any sense only if god is good itself that is 2nd case.

And finally. Why the existence of any objective standard proves that god is good? What if god is evil? We still have objective measure, and maximum value, the only difference is that we reachg reater good as we move away from god. By this definition good is absence of god, and evil is his presence. Quite opposite to what we get used to. Yet it provides the same explanatory power! And i'd say more. To me it's much more natural to assume that god is evil. If you want to believe god is good, you have to deal with all those atrocities, suffer, pain, evil that exist on earth, that makes you clearly uncomfortable, and makes it hard to believe god is good. Yet if you start from an opposite position and assume god is evil, then everything fall into place! God gives people false hope, he show off, it's obvious he would call himself good, he is petty. It's much more natural and easy to understand Bible or Quran while assuming god is evil.

These three objections that is:
1. No reason, evidence, proof, whatsoever that suggests OMV exist
2. Even if they do, how does it proves god?
3. Even if it proved god or even if god turns out to exist, why it necessarily means god is good?

To me they render moral argument unsound.
You see a grammar or spelling error in my post? Feel free to point it out, I'm still learning.