It doesn't really matter what their justification might be, Threats of violence against people for listening to music is a trespass of basic human rights.
but that's not what it is. It's not a prohibition against music, it's prohibition against group classes set to that music. I presume anyone can listen to any music they please in private.
Semantics. Do you have a right to threaten a group of people voluntarily exercising together? Of course not.
Since you do not have that right, You cannot delegate that right to another, which makes any claims of "democratically" derived law, invalid.