The militarization of space was going to happen eventually no matter what. It's a necessary precursor to colonization but also national security as the cost of access to space plummets.
Several countries have shown the capability of destroying satellites, not to speak of spy satellites and gps, and the fact that the spaceshuttle and its military sibling was designed to scoop up satellites and bring them back to earth.
Space was never not militarized.
I really dispute the idea that it's "inevitable", it's just that we live in an era where the standing army and intensifying competition between nations is the way things work. It really is not something that is ordained by god. Look at the Atlantic Charter and other similar documents that could have set the world on a different path if they had been taken seriously.