Earlier quoted context omitted.
To be fair to Microsoft this was a Lenovo laptop. Though why Microsoft continues to do business with a company that thought it was a good idea to install a root certificate (with a publicly known private key) onto every single laptop they sold so they could MITM some ads into websites is beyond me.
I have a Microsoft computer (a Surface Laptop) and it's not that bad. There are dumb news stories in the search menu and it pleadingly tries to stop you from using Firefox, but then the interface is pretty clean.
I actually have never experienced this. What I HAVE seen is that if you accidentally open a not-firefox browser, it asks whether you want to make it the default.