There is no separation. Secular vs. sacred is an artificial divide, because every action has consequences in reality. Mr. Eich here did not simply
take seriously some moral warnings, he acted on them in the form of donations to political organizations which worked to enact laws which affect real people's real lives.
When your job involves leadership of a large publicly visible organization, you are going to want to be on the right side of history slightly in advance of the people under you.
Everybody and everything is connected, and it's not just a matter of your sect vs another. Being at the head of a large organization means having a massive pyramid of people under you, supporting you. That pyramid is composed of an increasingly diverse group of people. It used to be almost entirely white men (imagine IBM or any other major corporation 50 years ago). Now, look at an organization like Mozilla, supported by legions of Internet-connected hackers with a staggeringly diverse range of views on social matters, with one in common: openness and inclusiveness.
You cannot expect a stable platform to lead from if an increasing number of the people who support you find your views that repulsive.
You almost sound like you think that someone owes this guy a CEO job? He could easily find a leadership position with a group composed of people who could support him based on his views.