This.I am also using a Microsoft account. I don't treat this any different than my android phone. Ecosystems gonna ecosystem.
While I completely understand, and support, the argument that this is unnecessary and doesn't get you, the consumer, anything, I don't get the rage over it as it is always coming from people who are happy with their Android or iPhone. They have their account on that, and often tie a bunch of shit into it, and have no issue but suddenly Microsoft does it and they start screaming. I find it very silly and a bit hypocritical.
I can understand switching from Windows to another OS for a number of reasons, but because you have to sign in with an e-mail address is not one of them.
Edit: I should add if the worry is Microsoft will know who you are... They already do. Microsoft has the most high-fidelity data on people of basically anyone, outside of maybe intelligence agencies. Why? Well the first big one is Office365. I'm going to guess most of you use it for work e-mail. Even Microsoft's competitors have been jumping on the Office365 bandwagon. Because that is all work related, all the data is very accurate. People will put in all kinds of BS for their Gmail, O365 being corporate tends to be extremely accurate data. They get even more for the companies that then use AzureAD for their authentication, which lots do. That they can then cross reference with another high-fidelity trove: LinkedIn. Ya they own that too. They are low-key about the ownership but they bought it in 2016. Again, the data on there is high fidelity being work related. Facebook has more data, but lots of it is garbage, LinkedIn tends to be accurate.
People think Google is big data... nah man, MS is bigger data.