Thanos Thanos:
One: he isn't important in the slightest, he's only notable for the depth of his social and class hypocrisy
Two: he's merely getting called out for taking a cheap shot at someone who did something silly when they were seven years old
Three: He's a comedian, it's kind'a his job. Was the joke "out of line"? Maybe, but then that's where the humour in some jokes comes from. He's Britain's version of a "shock comedian".
Four: He didn't actually call her a nazi, he was just having some fun with names and the fact the Royal Family has Teutonic heritage. Then again, maybe Russell does too. The surname "Brand" is Germanic in origin
The sad thing is though, there was a time when Russell Brand actually was mildly funny, for about 5 minutes.