People are entitled to their opinions but that doesn't mean those opinions should not have professional consequences. If you walk around your company saying you do not believe women are equal should the company not take action against you? (Even if you had done nothing discriminatory except state the fact?). Firing someone does not interfere with their freedom of expression and if your values fundamentally conflict with those of your company, it will be unsurprising if they act on that.
What he did was neither illegal or immoral. He opposed a change in the law regarding the definition of marriage, he should..as we all should be allowed to voice his preference without fear or retribution.
There are some moral viewpoints which the majority of people do not tolerate professionally. E.g. if the CEO came out as a Nazi would you say he should still be in the job because otherwise people might not speak their mind??? Clearly not.
So now we are equating this with Nazism? Sorry, but I fundamentally disagree with you and that a basic tenet of an equal system is that people are unafraid and able to voice their legally protected position without prejudice. If he was breaking the law or advocating breaking the law you may have a point, he wasn't however, he was merely, as thousands of others, objecting to a change in the legal definition of marriage.
If that position is prejudiced then we are free to criticise that view with arguments of our own, or as in the case of the CEO in question we can oppose him in the legal arena. That doesn't give anyone the right to threaten and punish someone simply because they disagree with you, which is pretty much what is happening here.
I have never brought up anything to do with the law. I am not referring to anything legalistic, only what I think it is right of the employees and customers of firefox to do. Protest is a fundamental part of freedom of speech and equality - no one is trying to force Eich to have different beliefs.
The issue is one of a legal definition and the legal rights of others. Of course you bought up the law, it is fundamental to the argument.
You have a right to choose for yourself whether you use Firefox or not, you do not have a right to demand it of others.