Their support for Israel comes from a misunderstanding; a mistranslation of the Bible where they think if they bless Israel, God will bless them. God said that to Abraham, the person, not the Israelites. Instead, the Israelites' lack of faith almost got God to annihilate them when He was talking shop with Moses atop Mount Sinai. Of course, God was just supposedly pulling Moses' leg, but the fact that God was one step away from annihilating the Israelites if it hadn't been for Moses' intervention showed that they are far from the same people that God made that promise to.
The fact that boomer evangelicals make up their minds on who to support based on bullshit mistranslations of Scripture goes to show how fucked the older generations were in their thinking. A Renaissance or Enlightenment monarch would judge who to ally with and who to fight based on how each potential ally or enemy can work for their influence. Evangelicals toss support behind Christ-hating Israelis because they mistranslate their own Scripture; it'd make more sense if they support the Israelis because they're secular Europeans colonizing a theocratic shithole, and that they're developing an economy that isn't just oil and bayonet rule, but no.
The fact that someone like Ted Cruz had that misconception in his head when he was talking to Tucker Carlson goes to show how this stupidity has infiltrated even the highest offices of the land.