You're looking at things through the lens of a ground-dweller, where by default, all high-energy events diffuse their energy through the environment in a matter of moments. Even nuclear explosions or asteroid impacts will diffuse in relatively short periods of time. Thus, it is an exception to encounter a configuration of matter that can deliver the sort of concentrated energy and/or mass meant to hurt somebody, and we can assume that they are deliberately created by an intelligence, place such exceptional objects into exceptional cognitive categories and create special laws for them, and so on.
In space, there is no such energy diffusion. Anything put into orbit is going much faster than all but the fastest bullets and are much larger to boot, and thus put any firearms you've ever seen to shame. If it's in orbit, and it's still useful which implies it has the ability to maneuver, it's a weapon. It may also be other things, but it is certainly a weapon; everything could be used at the very least to threaten something else. (Think chess here; even threats have real impact.)
Even if you can't agree with that, it doesn't matter, because everybody involved with space does and will continue to act accordingly.
(The signed agreements not to militarize space are quite pointless, really, and I doubt there's a single signatory to any such agreement that is actually abiding by it even if we stipulate for the sake of argument that a "mere satellite" isn't a weapon despite the manifest untruth of such a stipulation.)