Unfotunately, I will never use musopen.org for YouTube videos until there's a way to verify copyright. YouTube says this song is monetized in "some territories". Perhaps musopen can coordinate with YouTube?
Thanks for your advice. I have had problems too with musopen.org. Will not use.
Surely the right thing to do is to always dispute the copyright claim. I'm sure the claims are raised as an automatic service by YouTube to the claiming organizations. Disputng it means some human being at both YouTYube and the claimer needs to actually look at it. So it costs them to investigae. If your dispute is valid, they will just release the claim. Moreover if it begins to cost YouTube and the Claimers more against small channels, they may be eonomically impelled to modify the frivolous claiming ehaviour.