Also, whether there's a military presence in the area or not is irrelevant to their needs - the military doesn't provide tactical support in law enforcement actions.
I'm not taking the position that it's a sane use of resources or a necessity (I don't think it is)...
They are being told by one of the most powerful federal agencies (DHS) that if they take it, they are helping defend the country against terrorism (that was the goal of the gov program right?) then offered equipment at massive discounts. I can imagine some small-time local school exec or police officer would love to sit down with the big boys in DHS and feel important, then get to pat themselves on the back for making "their community safer" by simply writing a cheque.