For seven years, the tracking industry has used the TCF as a legal cover for Real-Time Bidding (RTB), the vast advertising auction system that operates behind the scenes on websites and apps. RTB tracks what Internet users look at and where they go in the real world. It then continuously broadcasts this data to a host of companies, enabling them to keep dossiers on every Internet user.[2] Because there is no security in the RTB system it is impossible to know what then happens to the data. As a result, it is also impossible to provide the necessary information that must accompany a consent request.[3]

In short, RTB makes it impossible for the user to know where his data goes, which is a requirement for consent.

Oh.... I thought it meant that those cookie banners were 'false consent' and therefore render the data collected to be illegal?

Please provide more info - I would like to learn more about this subject!