It’s simple: he spoke to an undercurrent of emotional resentment that a lot of people had and gave them permission to feel like they were good people (or at least not bad people) for feeling that way. Every seemingly logical explanation that the right twists into place in hindsight is only a justification for that gut reaction.
They want to feel good for having xenophobic, nationalist feelings. He gave them permission and said they were the good guys and everyone who disagrees is wrong. They only care about the facts that back up that perspective, everything else is conveniently discarded to defend their collective ego. 45’s narcissism helps him win this crowd because he’s been ignoring all inconvenient facts his whole life, and whenever that habit catches up with him he always has a scapegoat or 12 ready to go.