The Web browser company Mozilla prides itself on its commitment to openness on the Web, just not openness of thought.

Decades from now, people may wonder how the company whose manifesto is a collection of warm-and-fuzzy sentiments about the Internet bringing us all together became a watchword for the new intolerance. Ousting your new CEO for what is in essence a thought crime will do that, no matter how much you hail your devotion to “openness, innovation, and opportunity.”

Mozilla CEO Brendan Eich had contributed $1,000 in 2008 to Proposition 8, the ballot measure to amend California’s Constitution to define marriage as between a man and a woman. How radical was Proposition 8? It passed with more than 52 percent of the vote in liberal California. At the time, no major Democratic presidential candidate, including obviously Barack Obama and Hillary Clinton, supported gay marriage.

Yet Eich has been hunted down and effectively fired six years later, not for anything he did in his decades at the company, not for any change he wanted to bring as its leader, not for any misconduct, but for an unfashionable political opinion that he refused to recant.

Eich co-founded Mozilla. The company’s statement upon his elevation to CEO said that he “has been deeply involved in every aspect of Mozilla’s development starting from the original idea in 1998.” What’s more, his “technology vision and general acumen have quietly shaped not only Mozilla, but large parts of the Web over the past two decades.” Yet somehow Mozilla — not to mention the entire Internet — managed to escape the taint of his views on marriage.

What changed? An Internet mob — led by a dating website, of all things — came after him. When Eich was duly defenestrated, the executive chairman of Mozilla, Mitchell Baker, issued a statement that could have been dictated under pressure from Mao’s Red Guards.

She groveled for not moving faster: “We’re sorry. We must do better.” In other words, Eich should have been axed more expeditiously, which would have been difficult since he lasted about two weeks.

She resorted to double talk: “Equality is necessary for meaningful speech. And you need free speech to fight for equality. Figuring out how to stand for both at the same time can be hard.” Not that hard.

She fell back on Mozilla clichés: “Our mission will always be to make the Web more open so that humanity is stronger, more inclusive, and more just.” Yes, thankfully the enforcers at Mozilla are here to protect humanity’s inclusiveness.

Liberal defenders of Mozilla say it is the company’s right to fire its CEO. No one disputes that. An act can be legal and still foolish and blameworthy.

Other supporters of Mozilla argue that opposition to gay marriage is as morally toxic as opposition to interracial marriage. But opposition to gay marriage isn’t grounded in a hateful belief in anyone’s inferiority. No one has alleged that Eich treated gay people differently from anyone else. Presumably Barack Obama wouldn’t have publicly supported traditional marriage up until two years ago if it were tantamount to racism.

It turns out that when the left inveighed against “imposing morality,” what it meant is that it didn’t yet have the power to impose its own. Now that it increasingly does, the old live-and-let-live pose is abandoned, and the purge is on. The Mozilla episode is another indication that the regime of political correctness that characterizes academia is infecting the American mainstream. It will bring with it the same fear that haunts campus life. Fear of saying the wrong thing and crossing the wrong people. Fear of retaliation for believing the wrong things.

For decades, we’ve heard from the left about the need to fight authority and to resist conformity. Now it is clearer than ever that it wants to wield the former to impose the latter. Brendan Eich is probably not a culmination so much a sign of things to come.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.