Why does Israel have the right to exist?

Would you accept to see some people come to America, and says God in our holy book gave us the right to take this land (some state for example), so all the people here must leave, if they don't we'll use force as the Zionists did if you read about the creation of Israel committing massacres and rapes, displacing 700.000 Palestinians, and they assassinated Folke Bernadotte the U.N. envoy to prevent any peaceful solution, because they wanted to expand and take more lands from Arabs, so is it logical and ethical, to come and say: there was the kingdom of Israel 2000 years ago and now we want to rebuild it on Palestine's ruins?!

If the West wants to reconcile with the Jews after the Holocaust why should this be from the Palestinians' account. Now we have in Lebanon for example, 400.000 Palestinians who are awaiting to get back to their lands, they have been displaced through horrible acts by Zionists, and the Israelis refuse to give them that right, so why does a person whose ancestors lived here 2000 years ago have the right to return and build a Jewish state, while the Palestinians who have been displaced don't have that right, and many of those who witnessed what happened in 1940s are still alive!

Is it sth natural in this world to take a land by force, displace a whole population and build another state?!