Easy to see: Many many people use the desktop as temporary dustbin for unpacking zip file contents etc.
With a proper file browser setup you have no need at all for doing thigns that way.
To be honest, the whole short-cut idea of the desktop doesn't really work well at all with Windows.
It doesn't surprise me at all that people use the Desktop to unpack files and make folders to store programs and files into. I do so too, as it's intuitive and searching files in Program Files (or the Explorer) doesn't work. Did you ever successfully found your files by doing a search?
Windows desperately needs a 'Go to folder' kind of approach to fix that. Make it all relative and context sensitive.
(Hint: take a close look at Mac.
)
Oh, and I hate the fact that some developers make it cumbersome to uninstall a program.
