That says to me that Firefox is aware the ad experience did not put people first, and that Firefox broke their commitment. They are discussing internally how this was allowed to happen.
There is no ethical advertisement. At the root of advertisements are intentional psychological engineering used to manipulate people.
Given that there has been a context previously where it was welcome, there may well be contemporaneous contexts where ads could exist in harmony with independently motivated user objectives. Basically all of what I see today, though, ain't it.