While many people regularly apply the First Amendment to just about any scenario where one individual wants to say his bit in front of a less than enthusiastic audience, the Amendment (and the whole Bill of Rights for that matter) was much more limited in its original intent.
Until the 1890s, the Bill of Rights was seen correctly as applying to the Federal government alone, not state or local governments, and certainly not private businesses or individuals. In other words, if a state wanted to tell an individual to shut up, it was constitutionally allowed to do so. Notice the wording of the First Amendment:
“Congress shall make no law…”
The First Amendment originally applied to Congress… the Bill of Rights was meant to delimit the power of the Federal government, nothing else. This changed with the incorporation doctrine.
When the victorious Union forces were crafting the Fourteenth Amendment, they had to figure out how to apply it to each of the states with a national edict. Given the previous interpretation of the Constitution, the Fourteenth Amendment would not have applied to individual states, so its framers wrote in the infamous “due process clause.” This directly barred state and local governments from interfering with the free exercise of the rights granted in the amendment. Since then, the due process clause of the fourteenth amendment has been used by the Supreme Court to apply the Bill of Rights, and pretty much every other amendment of the Constitution, to state and local governments.
This set a dangerous precedent that has not yet fully run its course. The First Amendment has been applied to the states and counties (thanks to the incorporation doctrine), but it has not yet been applied to private property and businesses. Not yet, I say, because this is the natural progression of its interpretation.
For now, it’s not the case that you are allowed freely to protest or say whatever you want on someone else’s property. A business owner or individual property owner has every right to tell someone on his property to be quiet or to leave. There are plenty of angry people that think any private infringement on their “freedom of expression” is a violation of their First Amendment rights. This just isn’t the case. And if and when it does become the case, it will not be a maintenance of the principles of liberty, but their undoing.
There may come a time when, under the dubious auspices of the First Amendment, the Federal government outlaws religious expression in general. For now, this is not the case. Enjoy it while it lasts.