It certainly does say that, and that's really broad and vague. And it's hard to keep track of this whole thread, but I'm pretty sure the branch we're on sprouted from a categorical claim that there are no "buts" when it comes to free speech. But your article doesn't dispute that there are exceptions, and so it's fair to invoke the fire in a crowded theater to illustrate the principle for that purpose.
For anything beyond that, the value and relevance will depend on what point is being made by whom and how well you are doing in your responsibility to interpret and respond to those charitably. But linking to a long blog post and vaguely warning that it's "bad" without doing any further work to connect that to a contention in any given comment is just confusing and unconstructive.
The post doesn't appear to be disputing that the fire in a theater example is a legitimate illustration of the limits of speech under the first amendment. They just proceed from there to make a more general principle that this example can be invoked by people who intend to suppress speech. Which I also don't think is in dispute.
So I don't think that post has anything to do with anything, insofar as this comment thread is concerned.