The majority were largely refugees that were ethnically cleansed from the Arab world, so not sure that really changes anything.
> Again, a state built around one ethnicity that by its founding requires people of a separate ethnicity who were equally living in the same land to become stateless, that's wrong and should not happen.
Israel's founding did not require anyone to become stateless. The land was effectively inhabited by two separate groups that did not want to become one state, and rules by the British - then the British gave the UN the task of deciding what to do, and they suggested what everyone else who has ever looked at the problem has suggested, and what any five year old would suggest - split the land into two, and give one to each group. The Jews accepted this split - and the Arabs refused, and started a war to conquer all the area (and let's leave to the imagination what they would've done with the Jewish population in the area).
But, all of that is history at this point. I don't think it matters as much now - Israel exists and has existed for 75 years as a fully reocgnized state. It no more makes sense to talk about "it's wrong for Israel to exist" as to talk about "it's wrong for the US" to exist. Do we routinely look at any other country's founding and talk about them not making sense any more? Many of which were also founded based around ethnicities?
> Now, the Holocaust is nearing 100 years old, does the raison d'etre of the country even apply anymore and does it justify the current state of things which has not changed since then?
Countries don't need a raison d'etre to continue existing.
If by "current state of things" you mean the Palestinians having no state, I don't think anything justifies that. Unfortunately, I'm not sure how to change that - multiple attempts have been made at a peace process that gets the Palestinians a sate, which the Palestinians have refused each time. By most surveys or interviews I've seen, most Palestinians do not want peace with Israel - they want Israel gone. And to top it off, the last 15ish years have seen Israel become ever more extreme right, partially driven by the Israeli left's total failure to create a peace with the Palestinians - so it's not like the Israeli side is encouraging peace at this point, in fact quite the opposite.