Large scale immigration to a country? Can you please tell us what country you are referring to ?
Your replies have been fairly astute so far toastman, so I am hoping here that you are not going to tell me that Jews came to a place that wasn't really a country, and didn't really have inhabitants, in a meaningful sense of the word.
We can play a game of semantics here about the name of the place, its political status, and what the Ottomans, British, French, Zionists, or the Sharif of Mecca had decided to impose on its residents, but the fact is that the place did have long standing residents, who considered it home, and felt that, beyond a reasonable amount, immigration was not a good idea, as the place was full, or a full as they thought it should be.
Many Jews at the time considered they needed their own country, and as few where up for sale, Palestine was decided upon as a good bet. The problem was that they were too late. In the post war period, colonialism was fast going out of style, as Britain and France were already discovering. Israel was too late in the game.
And this is the root of the issue. The large scale movement of peoples must be one that is negociated and accepted, otherwise it can rapidly start to look like an invasion.
It absolutely had inhabitants. But Palestine was defined as a geographical region at the time, NOT a country, and that is not up for debate.