Its not a fact though its your interpretation. Hitler wasn't pro Israel. He was pro getting rid of the jews from Germany, that is the fact. He used the zionist cause for his own ends, that doesn't make him a zionist. Even if it was a fact its a deeply flawed argument. Saying something is bad because Hitler liked the idea: Well Hitler also liked building decent roads and dogs. But if my brother (a cat lover) was to use that last fact to show why I'm wrong for liking dogs I'd laugh in his face at how bad his argument was.

People can be racist against there own race, just like gay people can be homophobic so the defence that it wasn't antisemitic just because it was a Jew that said it doesn't work. Naz Shah accepts that what she retweeted was antisemitic.

If that (defending labour) was why Ken said what he said then he's not just bad at politics he's an idiot. Instead of saying Shah should apologise and having maybe a brief mention in the news his comments kept the story of Labours problem with antisemitism in the news. If his aim was to help Labour then he should have apologised as soon as he realised his comments had caused offence and were hurting Labour.