You say you use this to 'refute those who insist that Zionists have a right to ethnically cleanse a region because they claim they were there thousands of years ago and whoever is there that is not Jewish has no right because Zionists believe all nonJewish ethnicities were not there then too. '
I very definitely didn't say that either about ancient times or modern times.
I've mentioned that the Philistines (who came from southern Europe and then disappeared as a civilisation, killed and assimilated by the Babylonians) were there at the same time as the Israelites. There were many different peoples at different times, and huge amounts of population movement over the last 3000 years. It was an important and fertile area!
I have also many times said that in modern times, both Palestinian Jews and Palestinian Arabs lived in the whole of the Palestinian mandate. I only see Palestinians seeking to exclude Jews from 'people who belong here', not the other way round. Israel has 20% Arab citizens.
I've certainly never said that the ancient history is the reason Israel should exist. It exists because both Jews and Arabs lived in the land in modern times, after the fall of the Ottoman Empire. The land was partitioned according to the people who lived there: 20% was assigned for the Jews who made up 30% of the population. 80% was given to the Arabs who made up 70% of the population, including all of Transjordan (now Jordan) which it was specified no Jews should live in.
That was proposed because it seemed at the time that it was the only possible solution, given existing civil violence between the 2 groups. It may or may not have been the right approach, but I'm pretty certain any other approach would also have resulted in bloodshed. As it did in Iraq, Syria, Lebanon.
Partition was an approach taken in various areas of the world for areas which were coming out of colonial rule (the Ottoman empire in this case), where there was inter-communal friction which made a single country seem unsustainable. The Partition of India resulted in 1 million deaths and 10-20 million people displaced. It swamps the deaths and displacements in the Palestinian mandate because it's a far bigger population. Perhaps the big size helped in the end though, since despite remaining tension, 70 years on India and Pakistan are stable countries.
The Arabs never accepted the Partition of the Palestinian mandate lands. And the small area means that the ongoing violence can't be restricted to a border area but engulfs everything. I don't see a way to stability that way.