Brendan refused to apologize for the donation or even to acknowledge that it was wrong. Instead, he doubled down on it, saying in comments posted to this very forum that the gays kept asking for more and more rights, and he wasn't OK with that. It wasn't part of the previous bargain. https://news.ycombinator.com/item?id=15966490

Given that he refused to apologize, and that the pesky freedom of association exists, which can lead to problems for Mozilla like the Montgomery Bus Boycott did for the public transit system in Montgomery, it was overall positive for Mozilla that Eich resigned. That doesn't mean that Mitchell is a good CEO. It just means that things would have been worse.

There was no evidence that Brendan discriminated against gay employees at Mozilla.

> the solution was chastisement and a public apology

Not all gays are in favor of gay marriage. The solution was to let him have his political opinions, and simply agree to disagree, like adults.