If you pay attention to what he says about this issue, since he has spoken a lot about Palestine, it is clear that he opposes Israel. This isn't 5D chess, it's a simple rhetorical refocusing that is similar to how he handles almost everything because, even outside of "Does Israel have a right to exist as a Jewish state?" people are constantly throwing insipid gotchas at him that he tries to redirect to cost of living, listening to the expressed needs of New Yorkers, etc.