Sure, it's valid to disagree with Google's involvement in this project, but I find it incredibly hard to justify the claim that private enterprises traditionally don't equip armed forces. Providing technology and hardware to armed forces is something that private companies have been doing for centuries. Heck non-state groups selling arms to armed forces likely predates the existence of states as we know them. Most armies prior to the modern era were militias that privately purchased their own equipment.
This project is "assisting in killing people" to at most the same degree that developing munitions guidance, military radar systems, and sonar are "assisting in killing people" (I'd argue less since this technology is purely about reviewing reconnaissance data, not about the actual deployment of weapons) and private companies have been developing those systems for over a century.