I think that 1) the tweet from Saturday, reaffirming his commitment to CU, and 2) the fact that he was voicing his commitment to CU at appearances and in media interviews as late as Tuesday afternoon (gave his resignation to CU AD at about 8:45 pm Tuesday night from what I have read) is what people have found to be off-putting....especially when he pretty much implied at his intro in East Lansing that he had his mind made up on Monday morning.
I don't blame people for taking better opportunities, but I think that there is a point at which one should honor a commitment. If Tucker is the coach some people think, Sparty won't be the only opportunity he gets.
Let's be honest....if Frost (or any Husker coach, for that matter) had done this after a season, at this point in the off-season, we'd be pretty bent out of shape over it as well..