[written]

It can be seen as a message (as you say) to a wider populace that this is all getting in a wrong direction. If government is hiding from its own populace what its doing with drones, who should raise this issue? Why not people working on the drone program (regardless of where exactly). It's much easier for newcommers than incumbents I'd say, so it make sense some Google employees would be ones to protest.

You never know what will be the initial trigger for change, who will be inspired or whatever. Take this guy: http://www.ecns.cn/2018/01-02/286632.shtml Why should some basketball celebrity and his campaign have so much effect?