Except Zionism was started by secular Jews and Zionists today are mostly Evangelical Christians. Israel and its creation has always been colonial and not religious. Religion is mostly a fig leaf/cover for it.
To paraphrase from Ilan Pappe, "Most Zionists don't believe in God, but they believe God promised them Israel"
Not really a contradiction if you understand Zionism. Paraphrasing Theodor Herzl (recognized as one of the "founding fathers" of Zionism) "the anti-semites will become our greatest allies" in the late 1800s
Because anti-Semites would support Jewish emigration. White supremacists and neo Nazis would be glad to see them gone from the US. And they have an easy place to push them.
That, and Israel's importance today to US government is more about geopolitics and power projection than about ethnic/religious identity.
And also the Christian zionist angle other people have mentioned with Armageddon.