I've got no problem with spelling it as Labour. However, get over yourselves on the aluminum/aluminium debate. The British way of spelling isn't "correct", its just one way to do it.
It is the correct spelling for the British Labour Party, though.
Calling it "Labor" would be like if a Brit started talking about the "Farmer-Labour Party of Minnesota".
Or the "Australian Labour Party" when they use the American spelling as well.
Even though I've lived here for many years now, I still haven't bothered to learn why the party is "Labor" with no "u" here, when basically every other word is spelled the British way.