I don't think that's true. That was an insane contract and the number of places hiring that were also willing to pay it was limited. But even if it were true, it's Chicago. He barely has to leave. His kids don't have to switch schools, none of that headache has to happen.
It was a no brainer for him to leave. I personally think it's pretty childish to begrudge a guy for doing what he did. I can't really personally comprehend getting upset at some coach in his 50s for not coaching my favorite team. Lightheaded ribbing is expected and fine, but actually getting bent out of shape about it or still whining about it 2 years later when we appear to have benefitted from his departure? Who cares.