Well, let me ask you two questions.
Is Kathy Griffin entitled to a position on CNN? And, absent CNN, can Kathy Griffin no longer create distasteful "art" (and I put art in quotes for good reason)?
So by and large we're agreeing with a bunch of things, save for basically the line essentially of when an individual...within the realm of private life...is actually attempting to stifle another persons free speech. And ultimately, it's probably a reasonable thing to differ opinions on.
Most of your questions seem to come down to two things....
1. Are people "entitled" to whatever means they are currently using to engage in their speech?
2. If they are able to still speak in SOME fashion, is their freedom of speech actually being stifled/stopped?
First, before we get to either of them, I think we need to hit on the main thrust of my issue.
I think there is a difference between naturally occurring consequences and actively sought punishment. I think there's a difference between a response and retribution. I also understand that in many instances, and for many people, that can be a very thin line between these things.
You being upset by a radio hosts speech and resolving to no longer listen or partake in that stations advertisers is a natural occurring consequence. You actively engaging online activists to bombard advertisers in an orchestrated effort to get the specifically get the host fired is actively sought punishment.
A citizen writing an op-ed excoriating the DJ and his listeners and explaining why such thinking is harmful to society is a response; a citizen making demands and actively protesting outside the station until the person is fired is seeking retribution.
I believe that actively seeking to punish in extremely impactful ways (and I believe loss of employment is one of those things that absolutely would qualify) an individual for speech, specifically in which it's only transgressions is that you disagree with it, is antithetical to the concept of "free speech".
Now, as it relates to entitlement.
No, people are most definitely not entitled to their job, their column, their radio show, their website, their blog, etc. However, the fact that they are not entitled to it does not change the reality that such a thing is being threatened, in these hypothetical, simply because people have an issue with the speech the person is using. And I think attempting to silence, shut down, censor, terminate, or end a persons job, column, radio show, website, etc because you disagree with their speech, regardless of the fact they're not "entitled" to that thing, is against the principles of freedom of speech. Simply because they are not entitled to such a thing does not change the fact that you are attempting to in some form stifle the speech they're currently able to employ based singularly off your displeasure with what they're saying. To me, that is a clear transgression against that principle.
As it relates to question 2....
While we have established we are not talking about the government, and largely agree there, parallels can still be drawn. Just as I'm not a fan of "Free Speech Zones" (putting aside the idea they are established due to security needs as opposed to an attempt to simply place protesters in less obvious and visible locations), the notion that "you can still talk, just in a much more restricted way, so it isn't REALLY stifling" doesn't really fly to me. I do not believe one must remove
all ability of a person to speak to be able to infringe upon the ideals of freedom of speech.
By attempting to take away or remove an avenue that they were previously rightfully utilizing for speech, and of which they violated no pre-agreed upon condition to void that avenue, you are attempting to stifle/silence their speech to some degree. In totality or permanently? No. However, just like if I have $100 and you steal $10 from me, you have stolen from me, if I am able to voice my opinions over a radio show and you successfully get that taken away from me, you are stifling my speech. You have not taken all of my ability to speak, just like you have not stolen all $100 dollars, but some level of the act still occurred.