This is not true, they only killed the people who fought back, you have to understand that the British used to own the land and gave it to the UN. Its not ethnic cleansing if you leave people behind, they didint try to kill EVERY Palestinian.
This isnt a valid argument, religion is based on opinion and faith, if you said that "God told me to have this Lamborghini and I have permission to take it from its owner" it would be anarchy, if that actually worked in the real world everyone would be taking things. I mean, i support the Israelis but this argument doesnt really work.