I'm sure there's more to it. Off the top of my head:
The prisoners outnumber the guards. If this guy is going to end up with a cult following, especially one based on killing law enforcement, they could have a serious riot concern on their hands.
Moving them to a new prison, under the premise of rule 1, is not really going to be considered cruel and unusual or anything of the sort, because visitors are a privilege in the first place and all sorts of things can have it taken away.
Overall, you could look at it as the COs reacting to disrespect, or you could look at it as a safety move. Regardless of either option, they can use the latter as justification and it would make some sort of sense.