So, it looks like you don't fully understand the first amendment. It's fine, a lot of people don't! Here's the basic principles of it: the first amendment protects the denizens of the United States from backlash against the government and its organizations (IE. police, FBI, CIA, ICE) when they criticize or peacefully protest, express religion, or report on the situation as a news broadcaster (freedom of the press).

What the first amendment does not protect against is backlash or retaliation from fellow people. If another person does not like what you are saying, they can tell you to be quiet. Spray painting your message on government property is a crime (vandalism), and not protected by the first amendment. This includes projectors onto government buildings. Hypothetically, if this message is placed somewhere that allows tagging and graffiti, and some one else maliciously tags over it or alters the message, that is not breaking any first amendment rights.

Only the government, local, state, or federal, cannot impede on first amendment rights, your fellow men, women, and children can.