Lacking evidence to the contrary, it seems Microsoft actively approves this state of things. They have a human performing certification and content compliance, which involves actually installing and verifying these applications:
"Content compliance: Our certification testers install and review your app to test it for content compliance. The amount of time this takes varies depending on how complex your app is, how much visual content it has, and how many apps have been submitted recently."
With that statement, they must be 100% complicit in these scams, because it makes them money when someone bites, and because it keeps the number of apps in the app store up.