And, in reality, this very same argument can & should be made for a whole laundry list of various freedoms & rights.....

Just replace "express ideas" with....

Practice religion...
Get married...
Obtain healthcare...
Vote....
Live in US....
Be employed....
Exercise Reproductive control....
Etc......


Unfortunately, there's a whole slew of people who either
A. fail to grasp that the concept can be universally applied to all freedoms & rights
Or
B. Have somehow deluded themselves into believing that they possess an irrevocable exemption from being subjected to any restrictions of their freedom.

I can't claim persecution if, for example, I'm not allowed to speak at a football stadium at halftime. I can, of course, speak outside all I want, but i have no right to take the microphone and speechify.

Imagine if republicans started banning or shutting down via protests Muslim, pro-choice, or gay speakers. I see people taking things to the nth degree here a lot, where a person being moderately to excessively racist is equated to advocating for gas chambers. Now imagine if they did this to us (because some already do). A Muslim person would be banned from speaking because they're "promoting sharia law". A pro-choice person would be banned from speaking because they're "advocating mass infanticide". A gay person would be banned from speaking because they're "corrupting morality and promoting deviance".

See? This is the foreseeable future if we keep up these laissez faire do-nothin-but-yell protests that are largely a result of the simplicity of organizing them through social media; rife with faux outrage resultant from the crowd's peer-pressure osmosis. It's mostly a folly of youth representative of certain issues that millennials face as a generation (continuously feeling left out and powerless in politics while technology-induced ADD/media addiction and the subsequent self-absorption keeps us apathetic and unlikely to get involved at a deeper level).

Did anyone see last week's Veep? That was a pretty good demonstration of protests that are unhelpful and unhealthy.

Protests are excellent examples of freedom of expression. I encourage them to be used at any time they are useful.

Threats, incitement and criminal conspiracy are ideas we restrict in public and even in private.

Depending on the meaning of "restrict," I guess. It could be said that we allow these expressions, but the fact that we prosecute means there is a chilling effect, and that seems well and good. Civilization could be defined as the acceptance of restrictions on one's freedom for the privilege of living in peace in proximity to others.

If Congress passes a law that declares a person's ideas illegal, is that a prohibition? If the owner of a speaking venue declines to hire or rent out the venue to a person, is that a prohibition? If someone is speaking and gets booed down by the audience, is that a prohibition? If a person expresses their ideas and is simply ignored, is that a prohibition? If someone expresses ideas designed to foment violence and incite a crowd to lawless behavior like vandalism of private property or lynching a person, is it a prohibition to stop that person before they really get started? Or do we have to wait until the crime they're inciting actually happens?

I got questions.

publicly-owned venues, and only prohibits the government from blocking free expression. If a venue is privately owned, the owner can block pretty much anyone from speaking at that venue.

Booing from an audience is also an example of free expression.

Laws also exist against inciting riots. Those laws have passed constitutional muster. There certainly can be types of expression that are against the law, as is obvious from existing laws that have been tested as to their constitutionality. Slander and libel can also result in civil suits and damages awarded.

My post is general in nature, and applies to the general understanding of what the amendment means.

Private parties can allow or disallow pretty much anyone from entering or speaking on properties they own. Freedom of expression has to do with the government doing that.

Which is why I got confused about what you meant by a prohibition.