Markdown is not spec’d in kind1. Many clients don’t render markdown in kind1. They really shouldn’t to make client dev’s lifes easier if they want to keep their kind1 client simple.
Discussion
Couldn't amethyst add a long form content button down here with everything else making the option available for those that would use it?

They sure can .. but I don't see anyone typing ten thousand words of markdown on Android phone :-) ..
On a Tablet maybe .. but longform writers normally have a workflow ..and they are kinda already sold on to their editors ..
Plus there are few things about longform content - the image that normally goes on top of the post .. multiple tags .. a summary ..
And then there are curations .. if you wanna link chapters of book in a Table ( of content ) ..
And then there are libraries for offline reading .. as in download a book kindle style ..
That is a heart break .. but the point is longform content ( markdown ) ..no one would ever write on the web ..or on a phone ..
So not much of a loss ..
And we don't need another editor ( native nostr client ) .. all we need is plugins