Curious. Sometimes people do that sort of thing to avoid copy/pasting, but I wonder if in this case it's a poor man's way of getting syntax highlighting on the web: just screenshot an IDE instead of dealing with a syntax-highlighting-in-HTML tool.
It all depends which area you are in.
Microsoft's web presence in general varies widely. The philosophy appears to highly favor providing access to knowledge/content over standardization of form/presentation.
The scale of Microsoft's web properties is vast and they do not waste resources trying to get a herd of cats to goosestep.