It's not evangelicals, and it never was. While boomercons are the only group left with a (small) net positive support for Israel, this isn't for some esoteric religious reason based on a deliberate mistranslation of the Bible.

Their support comes from the fact that all of the media they take in paints Israel as a hapless victim that gets attacked by all of its neighbors for no reason. The only people they see saying otherwise are the people who also serve as apologists for every black murderer headed to the chair, so they (understandably) pay them no mind. It'll erode as their younger friends and relatives get more comfortable talking about why Israel is bad.