None of the three reasons presented are specific to Brave Rewards. They're all about the company and its investors, and so by extension the company's motivations.
If you believe the actual browser is siphoning off information to Palantir, that's an entirely different story.
But for now, this post just reads like a conspiracy theory. The browser's FOSS. Surely switching.social is capable of checking the source code for anything fishy, and using that as their ammo instead.