There are things I don't agree with that Mozilla does, but I will stand up for that one. The idea behind the "tiles" was to try to figure out a way to do privacy-respecting ads. And if you look at how it actually worked... it was actually a really good plan for how that could happen.

Mozilla's job is to find ways to push the web forward in ways that respect humans, and ads are, well, how the web mostly gets funded. So it's entirely within bounds for them to try to figure out ways to make ads work without invading people's privacy.