One of the founders, Brendan Eich, donated his money to take away the equal right for same-sex couples to marry in California (Prop 8). He never acknowledge that it was mistake, so I can only assume that he truly wants to see the marriages of same-sex couples erased, which is quite a hateful thing to desire.
Proposition 8 [...] was a California ballot proposition and a state constitutional amendment intended to ban same-sex marriage
So I fail to understand how this:
Even couple of LBGT employees of Mozilla Corp. defended Brendan Eich on their blogs claiming that there is no discrimination against them in Mozilla
Could be possible, I tried searching for their blog post, since the author didn't link it anywhere, but not knowing who they are I wasn't able to find anything. It could be true, but still, Mozilla isn't the whole California, if they are treated well due to company culture good for them, but that isn't an excuse to let gay people be discriminated outside of Mozilla
It seems to me like what everyone thinks is right, even if the proposition were made to "declare marriage a union of man and woman" it would just be a roundabout way to say "declare union between man and man/woman and woman not marriage" so... ban same-sex marriage?
While that's fair, actually funding something to take away the rights of another person, like this guy presumably did, is a lot more weighty than just having an opinion.
Loving v. Virginia (1967) and Obergefell v. Hodges (2015) ruled that interracial and same sex marriage bans violate the equal protections and due process clauses of the 14th amendment.