Why play psychologist at all? He thinks Allen can do the job and is willing to give him time to do it. I don't like it, you don't like it, but that's what it is. No need to pretend to understand Loomis' psyche.
This is the simplest and most obvious explanation. But, we live in a world where people want intrigue. They want conspiracy theories to be true. They want a true villain to hate.