There already is federation of deletion. It's not even something that needs to be implemented.
I have less of a defeatist attitude about privacy. Same way I don't think absitence is the only true way of contraconception. Privacy, yes, even if public spaces is possible. It's not easy, it won't just happen, but it is achievable. Needs a lot of work from a lot of people, but it is doable.
I don't expect you to change your mind on that.
Do note that is not for the foundation which runs and develops Firefox, but for the company. Still shit, but separate from the browser.