It appears that Jim felt the underlying violation (buying some recruits some hamburgers) was ridiculous, and, given the circumstances, was an example of the NCAA making a mountain out of a molehill. He seemed to treat their questioning with contempt. When you do that with an authority, you are basically begging them to exercise their authority.
I'm no defender of Harbaugh. I basically think he is a goof, but the NCAA gets its panties in a wad over this great burger scandal. Meanwhile, recruits are literally being bought and induced with NIL deals facilitated by schools and they have nothing to say about it. Their credibility is shot. They are too erratic in what they enforce harshly and what they dont enforce at all.