This is true of the vast majority of activists in any political cause. Most join as social signaling to their community that they are "one of them". Case in point, almost nobody interviewed for occupy Wallstreet could even agree on what the goal of the group was.
Particularly in this case, showing support is literally as simple as installing an app that does almost the exact same thing as another app. "sure, I'll do that and post to Facebook about it to show how forward thinking I am"