Section 7b – or "Updates to the Services or Software, and Changes to These Terms" – of Microsoft's Services EULA stipulates that it "may automatically check your version of the software and download software update or configuration changes, including those that prevent you from accessing the Services, playing counterfeit games, or using unauthorised hardware peripheral devices."
The list of services covered by the agreement doesn't explicitly include Windows 10. However, it does include your Microsoft account, which is an extensive part of the Windows 10 experience, as well as core features like Cortana – and that implies Redmond can disable any games you've pirated or devices you've "unlawfully" hacked. Enable Cortana (which pretty-much everyone using Windows 10 is going to do) and you're subject to the Services agreement.
Pirated gaming has long been a plague on the PC side of things, obvs, and many companies have tried various tactics to stop the steady drop of games leaking onto torrenting sites and resources leaking out of developer/publisher pockets. It makes sense that the company with the largest overarching control on PC gaming would be the ones to try and make a stand.