I would argue that European Jews during & just prior World War Two were initially refugees or potential refugees; later they became hostages. For much of the refugee stage their ultimate fate wasn't clear, & so national concerns over the ability to absorb them economically, or of potential fifth columnists, which might seem trivial when lives were at stake, were basically valid because the stakes weren't obvious. By the time it was obvious, it was too late to save more than a handful of those lucky enough to evade the SS & their allies.

After the war, however, the Allies confronted with proof of horror beyond their wildest speculation, did they help?

No. Not a bit.

Britain maintains White Paper restrictions; the US its immigration quotas. Truman proposes to the British they let in 100,000 to Palestine on humanitarian grounds, he's told to mind his business. Even at the UN—Pluralus makes a slight mistake when he implies Britain agreed to grant the Jews a homeland—the British abstained from Resolution 181 (well, at least they didn't vote no).

As Walter Laqueur writes in his History of Zionism, this is when the liberal humanism that had constituted the majority of Zionist views was repudiated. Revisionist (radical) Zionism, which unapologetically called for transfer of the Arab population & borders all the way to biblical Eretz Yisroel took over.

It's clearly a view that continues to inform Israeli leadership.