God bless the EFF for their many good efforts, but I don't think one is going to get traction in the courts even if 10,000,000 people sign it. There's no legal obligation for anyone to use Windows, and in cases where it's the only compatible option (like a Win-only mission-critical business application), there are ways to avoid getting upgraded to Win10.
I feel their pain, I really do. But there are ways to deal with it. Microsoft is not going to bend on this one, I'm quite sure.