Your cousin coming to your home to visit or asking you to live there is very different from him coming to murder you and steal your house and tell the world how he is right to life there and your family trying not to have their house stolen is literal terrorism
Why is it illegal? Because it the massive migration to Israel clashing with their foundational myth of returning to the region?
Nevermind, saw the linked resources.
Without looking at the sources, I'm going to assume it's because, genetically speaking, Palestinians and Israelis are almost identical.
Edit - yep... That's the kicker.
Wouldn't being genetically identical to Palestinians support the Israeli's case for being there?
Your cousin coming to your home to visit or asking you to live there is very different from him coming to murder you and steal your house and tell the world how he is right to life there and your family trying not to have their house stolen is literal terrorism