A great question, but not very relevant anymore. Let's set aside for a minute whether Israel should have been founded in that land in 1948 - it was founded there, and it's been 75 years. There are 9 million Israelis (or 7 million Jews if you want to break it down that way) that live there now. I was born here, my father was born here, my son was born here. Do I have less connection to the land, right now, than the million Gazans who are under the age of 18 and have never lived here? More importantly, what do you propose? That all 7 million Jews in Israel be relocated somewhere else? Where? Who would pay for moving an entire country elsewhere?
As for the question itself of why the Israeli state should be in Palestine, like I said, while I think it's relevant, it is a good question. Personally, I would've chosen to locate it elsewhere, but then I don't really care about religion or sentimentality "for the land" or anything like that. Practically, I don't think Jews really had another place to go - remember, most of the Jews of Israel were either fleeing Europe before the Holocaust, or were the survivors of the Holocaust, or were ethnically cleansed from surrounding Arab countries. It's not like they had anywhere else to go.
That said, I do question your premise:
> Approximately zero Israelis have a connection to Israel that wasn't created by immigration, invasion, and conquer in the last 100 years.
This is very wrong. For one thing, you're ignoring the 20% of Israelis that are Arabs/Palestinians, but I'll assume you meant the Jewish ones. There has been continuous Jewish habitation of Palestine for literally 2,000, since the Jews were forced out. If you look at the demographic history of Palestine (https://en.wikipedia.org/wiki/Demographic_history_of_Palesti...), you can see that roughly 100 years ago, 10% of the inhabitants of Palestine were Jewish. And IIRC, all of them got there by completely legal immigration, not "invasion" or "conquest".