I believe most of the FUD is, in fact, coming from those rivals.

Brave proposes cutting out a bunch of middlemen through the token market and making the browser something like an anticheat system: opt in and it does its best to serve quality ads while preventing click fraud.

There are a lot of details in the execution that matter to make this competitive, but the basic idea resolves many of the current conflicts of interest that make adtech a miserable market.