As assemblies of people, corporations have rights. In fact, the right of the people to peaceably assemble and petition the Government for redress of grievances is explicitly protected in the First Amendment of the Constitution.

So Facebook is an organization of what, robots?

Are you OK with similar rights being stripped from your hometown newspaper on the grounds that they are a "corporation", despite the explicit specification of the press as a protected entity in the First Amendment?

In America, corporations are people.

Citizens United v. FEC

This doesn't mean what you think it means. Not all rights that attach to people attach to corporations. The bill of rights doesn't uniformly apply to corporations, and different rights may or may not attach under certain circumstances.

More importantly, the government declaring something doesn't make true. See anything from the entire Soviet Union to the various attempts to legislate that π = 3.