I have now been accused of Blackmail added to writing racist remarks,stupidity etc just for putting a topic for discussion.

You got off on the wrong foot with the original question - it's no wonder people react badly if they feel they're being asked "are you a snob?" Then you bundled together a lot of different questions, some serious, some daft ("Should a Copper Song be only enjoyed if sung with a Sussex accent?"), with the implication that anyone saying Yes to one ought to say Yes to all - and the strong suggestion that anyone who did say Yes was a snob. Then you told us you had a hidden agenda, which isn't exactly likely to win you friends.

As Jack said, the context of the question (your 'hidden agenda') makes a huge difference to how people answer. If I discovered tomorrow that Jon Spiers was an Icelandic immigrant who'd grown up in a gypsy encampment in Bavaria and taught himself bandoneon from an old Astor Piazzolla record, it wouldn't make a blind bit of difference to whether I like his music - but it would make a huge difference to whether I considered him a typical English player. So the answer to "Should music of other countries only be performed or recorded by musicians from those countries?" is a great big It Depends - and the main thing it depends on is whether you've got any other agenda apart from enjoying the music.