Not surprising.
The British as a whole a ferociously ignorant about their own peculiarly checkered colonial past.
Some years ago I made some Brit silly-nanny's head explode. He thought he could come into a forum and tell Americans how bad we are because we once had slavery in our country...
He didn't have a lot to say (well, he did, but nothing of it was of any consequence) when a couple of us started laying out in graphic detal just how bloody Britain's hands are when it came to the slave trade.
He finally got all butthurt and left in a snit. Nothing funnier than a Brit trying to storm off in a snit. :)