People can sing in any accent they want!
Just don't try to tell me that a Brit singing in a pseudo-American accent is greater than the real thing. That is just plain silly!

If we changed it to another genre...it might help.
Can you imagine any British country artist singing - performing in pseudo-U.S. accent would be rated as a greater country music singer than say Merle Haggard or George Jones?
No, that would be daft!