They’re still very focused on having a primarily open source system, but they held a vote and it was decided that it’s best for the computer to actually work and then try to be as open source as possible after that.
They did offer the firmware before, but you had to go out of your way to enable it and they didn’t provide security updates, was considered unofficially supported. With this, they’re considered officially supported, on by default if needed, and get security updates.
If you’re curious about the vote they did, it was this one and Proposal E is what won. https://www.debian.org/vote/2022/vote_003#proposere
Not to mention the interesting bits of info you can find just by looking into the CEO of Brave, Brendan Eich. Plenty of reasons with him alone for someone to avoid the browser and search engine.
The big one that he likes to keep buried is that he donated money to an anti-gay marriage proposition in California back in 2011, which is what caused some of the pressure for him to step down as Mozilla CEO back in 2014 after being it for a few weeks.