He even provides an alternate hypothesis, that 'sitting' is a marker of poor health decisions not the cause of it.
I'm not sure what evidence you are looking for?
I've never actually seen a standing desk advertised, or even recommended, as a tool for improving cardiovascular health. So I don't see how they can be "rated" as such.
I use a standing desk sometimes because it breaks up the monotony of sitting, and because sometimes I want to stretch my legs. It does well in that regard, and that's what I see them being advertised for.