Why you are not up in arms against it is the real mystery
Because there are so many evil things that the government does, that no one individual can be "up in arms" against all of them, unless he wants to burn out in about five minutes?
Any one individual can only do so much. So, you pick the battles that you think are most important. I agree with you that this should be stopped, and AA has said the same. Knowing him, he's probably working on RKBA stuff, for example. With a bit of work, we stand to make some major improvements in NH this year, in that area.
Work on what you care most about. I'll work on what I care most about. He'll work on what he cares most about. Sometimes, there will be overlap. Sometimes, we'll all be working on different things. As long as we're all working for liberty, that's what counts.
This is absolutely correct, but there is one more factor:
Virtually the entire state of NH is covered by private, non-profit corporations that contract with local governments to provide low-use, high-cost law enforcement services. So whether or not the KPD takes possession of this one particular vehicle and slaps their logo on the side, they will still have an on-call assault team backed up by armored vehicles. So, if you want to stop these things from coming in at all, you are simply too late.
And how you frame any future protest will depend on your philosophy about such functions. Do you believe, as some here do, that everything now seen as a "government function," such as policing, should be in private hands? Or do you believe, as others here do, that this sort of function is better left in the hands of a (minimally-sized) government that is ultimately responsible to voters?