- It highlights Trump's lack of understanding of evangelicals. Evangelical does not mean you have to be of European descent and living in flyover country. To question Cruz's faith based on his father's country of origin is rather ignorant and condescending.
- It helps Ted Cruz's get out the vote effort with this segment.
Good observations. By continuing this attack, Trump does expose himself to the very evangelicals to whom he is trying to appeal.
I see where you are coming from with this, but I think this isn't a question of "European descent" and "flyover country" or anything like that. I think Trump is imposing his own experience on Cruz. From what I understand, Trump actually attends an Episcopalian church in Palm Beach and a Reformed Church in New York City. He seems to be a Presbyterian primarily by birth and upbringing. His mother and her family were apparently Evangelical Presbyterians from the Outer Hebrides in Scotland (a rural, traditionalist area). Scotland is an overwhelmingly Presbyterian nation. Trump may well see himself as Presbyterian because his family was from a Presbyterian nation. It's part of his heritage and identity more than part of his current church membership. Cruz's heritage is from the primarily Catholic nation of Cuba, so in Trump's mind maybe Cruz is really Catholic (or at least was influenced by Catholicism growing up). I don't agree at all with this line of reasoning, but I do think Trump thinks of religion in terms of identity as much as practice. At any rate, I don't think this has anything to do with Cruz's ethnicity.