My apologies, I was confused by your phrasing when it came to "not supporting" Israel. I guess you meant not supporting their actions rather than not supporting their right to their state. My bad for misreading.

But part of the reason Israel arguments get framed that way is the fact that there has been opposition to their existence as a state since day one. There are still many nations who refuse to "recognize" Israel as an actual country, and the idea that they have no right to exist isn't totally fringe or laughable.