You bring up some interesting points: there are many human rights abuses in China and Russia. Tibet too. But these are not relevant to this discussion. And there is no such "right to exist" for countries. People have a right to self-determination. All people have this right. The reason Israelis bring up a "right to exist for Israel" is to seek confirmation for their historical narrative. This narrative is under attack and has been for the last 30 years (Benny Morris, Ilan Pappe, etc.). It's hard to pretend Zionism is not a colonial settler project. It's getting harder every day. There was a strong, distinctive Arab-Palestinian identity and this was a dangerous threat to Zionism. In 1948, there was no longer an option to buy land gradually, bring in immigrants, and build a Jewish nation. This was a time for a different sort of action. Depopulation and dispossession.

But I digress.

The actual history, and this is the history of my family, is that the Haganah orchestrated a terror campaign in late 1947 and well into 1949 to ethnically cleanse Palestine of its Arab population. They did not discriminate between Christians, Muslims, or Jews. In Haifa, they rolled barrels full of explosives down the hilly roads. The Haganah also drove around the city in trucks with loudspeakers warning the residents in Arabic that they would be killed if they did not leave. They referenced the Deir Yassin massacre. Of course this worked. Haifa was emptied. This was repeated, although with different tactics, Jaffa, Lydda, and over 500 other smaller villages.

The simply fact was that a viable Israeli state was not possible with that many non-jews living there. Over 750,000 people were dispossessed of their land. Half the population was ethnically cleaned. This is a war crime. It's also immoral.

Depopulation, dispossession, and colonization are valuable tools in "state building". But in the case of South Africa, it didn't last.