Israel isn’t fighting just the bad neighbor though, they’re using that bad neighbor as an excuse to kill many good neighbors too. All Palestinians are not all bad, some are innocent.
They actually weren’t given it by Britain after WW2 either, that’s not even close. Fresh Jewish settlement in the area began somewhere around the 1900s-1920s, and they actually purchased the land with gathered funds for the purpose. Life between the Jewish settlers and the Palestinians was initially peaceful. I’ll warn you, I’m a history guy, I love this stuff.
History is an ugly thing, certainly, the important thing is that we do better, and learn from the errors. This is how we can avoid living in such miserable times as our ancestors were often forced to, so often making foolish choices and burning their own countries to the ground out of hubris, like Germany or Japan in WW2 did.
The first Arab-Israeli War was a little more complicated than that. Jewish militias were actually conquering land at that point in something called Plan Dalet, it was something of a civil war in the broader region between the Jewish and Palestinian factions. After the Israeli declaration of independence, yes, a large coalition of countries did try to eject them. It was won by the Israelis though, and they were rewarded for that with gains. These wars do not give excuse to kill the descendents of those people, though, right? Each person should be judged for what they do, not their fathers, or their neighbors.
Don’t think the Israelis are innocent angels that never conquered or committed atrocities in their early history either. It was a very ugly time with both sides being pretty horrendous at different points. Modern Israel has taken steps at different points to be better than that though, returning to the peaceful ways of the original settlers under people like Rabin, before Netanyahu took over. They can do that again, it is not too late.