You also need to remember that the places we're talking about are de facto public spaces due to their practical monopolies on speech. They are private spaces legally and the companies who own them can be as discriminatory as they want in regards to who they allow to speak from a legal standpoint, but they shouldn't abuse their power to do so.
If they do discriminate too much, they should be regulated to be neutral places for speech, considering their excessive clout. A future where a select group of companies control what people hear, discuss and think is scary.
The analogy is appropriate in the sense that its not the "shouting" that is offensive, but rather that the message is considered offensive in the private place where it is expressed against the wishes of the owner of that private place.
"If you are only able to speak freely when no one is forced to listen to you - are you then allowed freedom of speech?"
This isn't some guy shouting in the street or some other public place (who, funnily enough, everyone usually agrees with their removal), but someone shouting on what is effectively private property.