Come the fuck on, really? Are you really asking someone why they would click the button that says download and is prominently displayed and then acting like they are stupid for expecting it to download?
99.9% of Windows users do not use win-get, and you know this. Stop pretending that bad UX is just the user being stupid.
WHY? Why would you ever do that? It is not "you are doing it wrong" it is "you are wrong for doing it at all". Even Windows got the memo and got win-get now....