Let’s spell this out in the simplest terms possible.
Israelis came to a land with its own native population. They wanted to live in the land and the land was not very large. (Israel is a small country.)
That required that the people who were already there be removed.
This was done in stages. Some of the early parts were done by buying the land, generally from landlords who didn’t live in Palestine, then evicting the natives. Most of it was done with violence, starting with the Nakba.
The project of Israel is to create a Jewish religious-ethnic state where there hasn’t been one for about a couple thousand years.
Those people also breed faster than Israelis.