At least it was a small scale experiment and not something that rolled out to the whole install base, I use Firefox on a couple of computers and didn't see it myself. But should you really need user feedback to know that inserting an overlay that looks like in-page ad content is a bad idea?
They are completely out of their depth and not fit for their job.
Trust me, they're politically aware of what they are doing, and are only gauging outrage now. Give it some time and they'll figure out how to leverage the outrage, as they did before.
Never let a good crisis go to waste, and all that.
Mozilla got rid of their founder, Brendan Eich, for donating to a California initiative against gay marriage. Now we see what that costs us.
Short answer: Well, compared to FF and the fine article that we are commenting on ... yes, it's certainly a model that FF could adopt!
Long answer: I don't see ads in Brave. I don't recall even installing any third parties to block ads. As far as the adtech space goes, Brave is indeed more ethical than FF (or Chrome, or Edge).
Now if you are of the view that, ethically, blocking ads is a bad thing, then I'm afraid we cannot actually discuss this any further, because there are very few arguments that will get me to change my mind about blocking advertisements, not least of which is the ad under discussion, i.e. "FULL-SCREEN-IN-YOUR-FACE-COVER-EVERYTHING-AND-STOP-THE-USER-FROM-DOING-ANYTHING-UNTIL-THE-AD-IS-DISMISSED" type of ad.