The White Paper limited Jewish immigration for the entirely absurd reason that Palestine could not possibly economically support so many people without impacting the existing population - even as it admits that the Jews that immigrated so far has had no problems integrating and growing the economy. It is a wonder that the population of the area is increased many times over since then and yet somehow Israel hs a better economy than its more-roomy neighbors. Imagine that.
The White Paper also infamously capitulated to the Arab demands that Arab land sales to Jews be limited, in an amazing bit of enshrined political bigotry.
Unsurprisingly, the White Paper does not address the huge amount of illegal Arab immigration into the country. Only Jews are deemed a threat to the area.
In reality, of course, the reason is more clearly indicated here:
The lamentable disturbances of the past three years are only the latest and most sustained manifestation of this intense Arab apprehension [...] it cannot be denied that fear of indefinite Jewish immigration is widespread amongst the Arab population and that this fear has made possible disturbances which have given a serious setback to economic progress, depleted the Palestine exchequer, rendered life and property insecure, and produced a bitterness between the Arab and Jewish populations which is deplorable between citizens of the same country. If in these circumstances immigration is continued up to the economic absorptive capacity of the country, regardless of all other considerations, a fatal enmity between the two peoples will be perpetuated, and the situation in Palestine may become a permanent source of friction amongst all peoples in the Near and Middle East.In other words, Arabs riot and murder and rampage when Jews move in, so if we have a choice of saving millions of Jews from certain death in Europe or upsetting Arabs who are quick to riot, it is much better to let the Jews die. Jews don't make as much trouble.
The fact that Palestine's economy was almost entirely the result of Jewish immigration is ignored. Economic reasons are the fig leaf of British fears of Arab terror, and Arabs then as now used terror to manipulate Western fears and policies, something I recently called the diplomacy of fear.
Against this backdrop. the World's Fair opened up in New York. The official British government of Palestine had no interest in exhibiting there, so the Jews of Palestine created their own exhibit. It is instructive to read Chaim Weizman's radio speech to the attendees, as it lays out the Jewish reaction to the bigoted and ultimately genocide-friendly White Paper. He makes the points that while the White Paper is immoral, it will not stop the ultimate rebirth of a Jewish state, that it was Jewish sweat that built Palestine up from an ignored slum to a major player in the Middle East.
Notice also Chief Rabbi Yitzchok Herzog's address, which was written before the White Paper, emphasizing how the Jewish return to Palestine has ecomonically benefited their Arab neighbors. Rather than talking about displacement and colonization, as is commonly charged nowadays, the Jewish leadership of Palestine always and consistently spoke of a win-win situation where Arabs and Jews both prosper.
The Arab leaders always pretended that Palestine was a zero-sum game, and the British White Paper codified that thinking. The Jews and the facts bore out a completely opposite conclusion - Palestine could and did turn into an economic powerhouse, benefiting hundreds of thousands of ordinary Arabs who moved in to take advantage of the Jewish-built economy.
Then, as now, outsiders pretend that they know the best solution to the Jewish "problem", and they come up with sometimes well-meaning plans to solve this problem. And then, as now, if their ideas end up accidentally resulting in the mass murder of Jews, they can say "oops - but we meant well."