I totally get your gripe with Gibbons. But IMO at this point, evidently players enjoy playing for him and management enjoys him as well. Getting rid of him would likely cause more harm in the clubhouse than good than by hiring a more sound manager. Getting rid of Gibby after 2 deep playoff runs also sets a bad precedent that success is not rewarded in the organization and could prevent players or other regarded FO associates from wanting to work there.
Also, really you look at a lot of managerial decisions basically in every game and you realize that it can get much worse than Gibby. And there's really only a handful of options that I can think of that would be better than Gibbons tactical-wise.