Probably: Such songs are probably populated older/old-fashioned moral principles and old-style heroes which come into conflict with current-day morality.
This is the context. The quotation doesn't seem to be fully correct. Also the OP should have posted the URL/link. ---------
EDIT: Wanted to say: Such songs are probably populated with older/old-fashioned moral principles and old-style heroes which come into conflict with current-day morality.
Mind you, populated doesn't resonate with principles, but ...