When Joe Biden is referred to as being "Irish Catholic", it's commonly understood that this means he comes from an Irish ethnic background. That his ancestors were Irish, not that Biden himself is from Ireland. Because that would be silly.
But let a reporter covering Barack Obama's visit to Ghana casually refer to the President as "Kenyan" when speaking with a Ghanan citizen, and WorldNetDaily's reaction is, predictably, 'MSNBC reports that Obama was born in Kenya!!!'
English must be a second language for Birthers. And I have to assume their first language is Swiss, which would explain their obsession with de Vattel.