This may be a good summary of the blog post, but in my opinion it is an uninformed understanding of Elm and Elm's history. JavaScript FFI isn't and never has been a "critical language feature". Rather, people discovered an implementation detail that allowed them to create thin Elm wrappers around JS libs (think Elm interface for d3, leaflet, moment, etc...). This was (rightly IMO) seen as undesirable for multiple reasons and 0.19 closed off the loophole at the compiler level.

As for being banned from the community, I keep seeing this claim but have never seen or heard of such things happening. Sure, there may be a negative reception to folks who keep wanting to re-litigate a decision that was made over and over, but nobody has been banned from anything.