IMO the proper solution is government agents have no more access to certain weapons then the public. That was the whole purpose of the 2A, making laws and court decisions giving one more than the other neuters the reason for the 2A.I can't believe I have to keep repeating this to you. Private civilians and public servants is not equatable.
I have no problems with civilians owning and having military weapons.
I have a huge problem with cops owning weapons of war since the people they will be using them on are the people they supposedly serve. Especially when the means for equipping these war machines comes from theft.
I am saying you shouldn't have the funds in your department to build/own/maintain a mad max battle tank.
Your last question is plain silly, is the armor an offensive weapon? I wonder why some states with the support of their cops are working to outlaw civilian use of armor?