If the advertising industry is such a powerful force of mind control that we literally have no free will anymore, then why did they let _you_ figure it out?

You're giving them way too much credit. Do you notice how the world is full of failed advertising campaigns? How the world is full of failed companies and failed products that the evil geniuses in advertising weren't able to make people buy?

There's a world of difference between 'we can use some principles from psychology to try to exploit people's fears and make them more interested in our product' and 'our unlimited powers of persuasion make free will an illusion'. And despite the hype, most big-data, machine learning, 'downloading your thoughts from Facebook before you've even had them'-style targeted advertising amounts to showing you ads for the thing that you just bought.