The obvious reply is: great, then we're not needed, let someone else do it!
That's an excuse people without any morals often use. It's up to each one of us to do the right thing.
After all: “The only thing necessary for the triumph of evil is that good men should do nothing” - or I would add that evil also rises when "good men" actually do the evil thing "because otherwise the bad men would do it anyway."
Google likely has the most advanced AI tech in the world right now. That means if that they allow the US government to use it, they will be directly responsible for accelerating the progress of autonomous killer robots or making them real in the first place. After all, I don't see too many other companies with AI that can learn the Go game within days and beat world champions.
I think DoD/Pentagon put up the funding for what later became Google maps. Not to mention the GPS constellation we all enjoy using.
Its a shame progress has to be made through these channels but it has proved very effective in the past.