But how do you know the people who can't play instruments don't have songs inside them? Most people don't actually ppay instruments. That's sort of rhetorical, because it's not a question expecting an answer.

"Allowed" - I suppose I was using that in an odd sense. Not meaning that people have to get someone's permission to do something, but rather that it's possible for a culture to put certain activities out of reach. "It's not done" as my mother might have said, though not of singing.

I don't actually think this is a particularly American thing. Historically song collectors in America found no shortage of people who were happy to sing unacompanied. I think it's more a modern thing, and as normally happens, America tends to be a few years down the road.

In this case I think it's a bad road, if it dries up the voices of people who aren't into playing instruments, or might sing better without them sometimes. And I think in the English-speaking countries of Europe folk people at any rate have probably been travelling down it in the opposite direction over the past few years.