But Firefox good…?

Yes! They are the most important alternative to major corporate backed browsers, helping sustain a diversified browser ecosystem so that no one company can monopolize the web, and push it toward standards that reinforce their monopoly. Google has tried to lock down the phone, app market, browsing experience that sustains their ad networks, and regularly pushes new standards that de-emphasize things like RSS, and that break ad blocking functionality to sustain their monopoly and invade privacy.

Firefox reverses or mitigates most of those and are explicitly driven by a mission of sustaining an open web with standards that don’t bend the web to corporate dominance. Google’s cheeky dont be evil mantra was in reference to exactly the things they are doing now, and it’s a little too on the nose to their actual behavior so it’s no longer a slogan of theirs, cheeky or otherwise.