If Google charged for the same services instead of providing it for free, would they make the same amount of billions? I assume everyone would agree that they would make way less. So the exchange in value is asymmetric and it still sort-of makes sense that you get some money for the outsize value that your personal details represents to them.
What's wrong with that, though? That's the essence of a lot of business - I take something with a certain amount of value to you and find a way to make it more valuable to someone else, then I capture the value I added along the way. The guy who sells flour to the baker isn't getting cheated because the baker can sell the flour for more than he pays for it once he puts it into a cake.
Nothing wrong with that, but likewise, what is wrong with trying to make money off of Google making money off of your information? At some-point, if the asymmetry is so large, it does make sense to try and capitalize on that.
