Your definition would place almost everything into one category: lethal weapons. And that isn't very useful.
The fact is, we need to scale down the militarization of police across the board, not debate how quickly or in what form advanced military technology should be given to the police.
The possibilities really become clear though internationally. If foreign governments, such as mexico, recruit drones, they might well solve their violence problems pretty quick.
For what it's worth I actually agree with your premise: I would like the police's capabilities limited as well. However, part of being rational is questioning weak arguments regardless of whether they support your point or not.
Just taking your conclusion as an axiom with no support is not particularly conducive to reasoned discourse. (This is why arguing religion with the truly devout is rather difficult--God is axiomatic to them.)
Logic is the best tool we have--save perhaps for the scientific method--to make decisions. It's worth maintaining regardless of the issue in question.
So yes--there always need to be shades of gray. Reasonable people reasonably disagree on almost every issue, because basically no nontrivial issue that isn't contrived is entirely obvious.
Perhaps you are fundamentally correct and your arguments stronger--I certainly think so. But this does not mean the issue should not be discussed. I've been wrong before!
Anyhow, I've gone well off-topic now, and I'm typing this on a cell phone. I think discussion is always useful, and it took me an absurd number of words to say that, do I'll say no more.