That’s great but - for the most part they are completely uninterested in that information.
That’s not the product.
The “product” is all the stuff you do on other websites. Stuff you buy. Places you visit. Other Social Media and Forum activity. Your ISP. (and here’s where they will know who you really are) That’s the data they aggregate - your name isn’t really that important.
Facebook will likely know that you are using aliases - and that itself becomes a piece of demographic data.
“People who use aliases and fake personal info” becomes a dataset.
I certainly hope, never having gone on Facebook, or registered on Facebook, will give me some protection from being TRACKED anywhere.