Well seeing as the UK arguably started the war in the first place I'm going to go ahead and say it's pretty effing relevant to the history of the country. Whilst I know more about WWI, I do know quite a bit about WWII though not the Pacific theatre. That's probably because, y'know, we were focused on Europe and Africa and hence that's what I know most about.
I'm willing to bet than less than 1% of British people would be able to give the date of the attack on pearl harbour, most likely because it happened on the opposite side of the planet and we'd already been at war for over 2 years by then.
You don't have to get bent out of shape because someone from a foreign country knows more about their own history than yours.