> It is an act which is protected by the First Amendment in the US Constitution.

Which is just a piece of paper. It has absolutely no power to protect you. Only a government that respects it can do that, and it's a certainty that our government will, from time to time, completely disregard that document when it feels the need to.

People have good rational reasons for hiding all sorts of legal activities they participate in.

Because law enforcement and the justicr system do not strictly obey the Constitution.

To put it another way: you can't rely on the Constitution to protect you during a protest against violations of the Constitution.

During Occupy I remember cops targeted a protester that had driven in on a company vehicle and told the company to get him fired.

The reality is that you night be illegally targeted and profiled based on data that is freely accessible. Robbery is illegal, yet it still makes sense to avoid behavior that can get you robbed.

Imagine attending a left leaning protest, having your participation recorded (unknowingly) forever by your phone, and then having a right wing, authoritarian government come to power and use that forever information to round up yourself and your friends.

Or imagine a left wing authoritarian government targeting lockdown protestors.

We should all be concerned about wanton data collection.