> When I want to browse privately I'll do it a different way.
And that's great for you. But a reasonable society at least attempts to look out for the slowest of us. Sometimes that means social assistance, here it means defaulting to protecting people like journalists, those with unpopular (but legal) opinions, people supporting or seeking an abortion, and others looking to not be stalked, either by corporations or former associates.
Your ability to protect yourself doesn't make a difference if everyone else is tracked and monitored - either because you are suddenly the only user that needs to be unmasked, or because predicting what people will do, buy, look at, and click on relies on getting most everyone - and not having your exact data isn't going to throw the model off that much.
In summation: privacy is a team sport.