There's nothing new here, a company can have a crap tech stack and still build a successful product if it has a competent team and good leadership.

This was I imagine a bit of a PR problem for FogCreek, because at the end of the day they were using Visual Basic to build a Windows-only website, not exactly the most awesome stack in today's world (or yesterday's for that matter).

It's normal that they want to communicate to the world the fact that you won't have to learn their custom version of Visual Basic in order to work there. It's also normal that people aren't giving them a pass that easily.