IMO you're overthinking it. Capitalism, free market, there's kind of no place for "fairness" here. Clearly it wasn't a sound business decision for Mozilla to have a CEO that holds these opinions, you can't force people to support something. I personally boycott products because of animal cruelty, can you tell me how is this any different? It's my right to NOT buy stuff, and my reason could be as simple as... uh, thinking the CEO is ugly, or as deep as having strong philosophical differences with him, or somethingI don't know...On one hand, my purely emotional reaction to this is "fuck yes!"
But then I wonder if punishing Mozilla and Brendan Eich for something he did years ago is the right thing to do. After all, Mozilla as a company is not anti-gay, and I doubt he would have made it anti-gay. And his donation to Prop 8 was done in private and without the use of Mozilla money or their support. And I tend to not be for the public lambasting of people for what they choose to do and believe in their private lives. It feels a little hypocritical.
I mean, as unfortunate as it is, a LOT of Californians supported Prop 8. Should all of them be hunted down and lynched for it?
Also: I hope Mozilla is around for a long, long time. I recently switch back since Google started fucking with the simplicity and speed of Chrome. and Firefox's new beta is fantastic. The first time in years that I can honestly say it's better than Chrome in pretty much every way.
People decide to not buy stuff based on colors, brand names, shapes, etc. - This is not any different, and if anything there's an actual reason behind it. I'm perfectly okay with this.