Why do police officers and federal employees harass First Amendment auditors?

First Amendment auditors are not doing anything illegal. All they are doing is taking video of whatever they can see in public. They stand outside of federal buildings such as post offices, courthouses, police stations, and military bases. They are usually met with confrontation by people who work in the facilities. There is nothing illegal about filming or photographing federal buildings. Why don't our police officers and federal employees know our First Amendment rights? These auditors have every right to take pictures and video of police officers and federal buildings. The First Amendment allows anyone to take pictures and video of anything and anyone they see in public. If a police officer asks for their ID, they are not required to give it unless they have committed a crime. I fully support the First Amendment and no one should be harassed for doing a legal activity.