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.
Also, I know this is the internet, but disapproving of one person doesn't mean that you're promoting another random person that wasn't even part of the conversation. If you want to bring Bezos in, at a minimum you're required to find a single person, living or dead, who thinks that Bezos's donations were fine but Eich's were terrible.