They were being sarcastic

I think they were pointing out how the logic is inconsistent even on its own terms

Yes, very sarcastic as FuckyWucky said. They always make these sorts of claims for other people but never apply the same standard to themselves. I do want to be clear that I don't think that the zionist claims have any merit. Lots of people have lived there throughout history and the idea that one of them deserves to build an ethnostate and exterminate everyone else is horrific.