The oxidizing atmosphere is not due to chance. It was created by early life that exhaled oxygen, and killed off its neighbors that couldn't handle it. Hence, I don't think the goldilocks oxygen levels speak much to great filter questions.
Actually, the neighbors that couldn't handle oxygen got forced underground. They live in the mud under the deep sea, in digestive tracts, etc.
Well, some of their descendants are still alive, yes. But I believe that there was a lot of dying involved in that process. More than I think is implied by the phrase "forced underground".
If it's worth saying, but not worth its own post, even in Discussion, it goes here.