Not so ironic now - as there aren't really good alternatives to a build step with a static site. But my opinion is that that may change now with the adoption of HTMX for static sites. There doesn't have to be a build step since you don't have to build full pages from their constituting parts.

You do realize that HTMX is a Javascript library?

Of course I do

Nothing ironic here. It's a different domain problem and they're using a different domain solution for it. The generator might simplify an otherwise much more complex problem down to its essence.