Just some food for thought from a different point of view, not that I care to change anyone's mind.
If somebody is able to monetize and profit from my data, just for the fact that I exist, in a way that I would not be able to even if I kept my data to myself by not allowing access, why not? In return I get to use many useful services and products for free.
I'm not losing any time, money, or effort for existing and having my data collected. I certainly wouldn't gain any of those things if I didn't, and in fact it takes more effort and sacrifice in terms of resources I am able to utilize, just to keep my data to myself, which isn't worth anything to me to begin with.
Unless some extremely illegal activities are involved, or the person has a habit of regularly making mortal enemies online. Then maybe those would be bigger reasons to keep one's data private.