Eich publicly supported Proposition 8, and donated a large sum of money
It was not deliberately public — only inasmuch, as largish donations must be registered (in violation of the First Amendment, which is usually understood to protect anonymous speech).
all to deny certain people the right
Whatever. My point was, 52% of California voters voted for the same thing. Which means, the entire State should've been boycotted until it purged those thought-criminals somehow.
He was a bad cultural fit for Mozilla.
He was a perfectly fine "cultural fit" for Mozilla for many years before that, and would've remained just fine after that — just as Mr. Thiel remains fine for Facebook.
But the boycott threatened to dent Firefox' market share and that is why they panicked. The fears were completely unjustified, of course, as Chick-Fill-A has shown, SJWs lack the stamina for any sort of long-lasting damage.