Last month’s passage of California’s Proposition 8, which banned same-sex marriage, unleashed anger among gay and lesbian Americans. One target: Marriott Corp., mostly because the company’s founding family and current CEO, Bill Marriott, are members of the Church of Jesus Christ of Latter Days Saints. See this and this and this.

Mormons, of course, played a crucial role in passing Prop 8. News reports say that half of the $40 million spent to support Prop 8 came from LDS members, who also canvassed neighborhoods and staffed phone banks. This is ironic, at the very least, as Hendrik Hertzberg noted in The New Yorker:

You might think that an organization that for most of the first of its not yet two centuries of existence was the world’s most notorious proponent of startlingly unconventional forms of wedded bliss would be a little reticent about issuing orders to the rest of humanity specifying exactly who should be legally entitled to marry whom But no.

But why go after Marriott? According to my friend Bob Witeck, who runs a consulting firm called Witeck-Combs that specializes in gay issues and advises Marriott, neither Bill Marriott nor members of his immediate family donated to the campaign on behalf of Prop 8. What’s more (and this is undisputed), Marriott as an employer has an exemplary record around diversity in general and LGBT employees in particular. It gets a 100% rating in the Corporate Equality Index (PDF), an annual survey of corporate practices done by the Human Rights Campaign, an LGBT advocacy group. The HRC’s inaugural gala next month will be held at the Mayflower Hotel, a Marriott property in Washington. GLAAD, an activist group that focuses on the media portrayals of gays, has held its awards ceremony at Manhattan’s Marriott Marquis.

So it would appear that the Marriott Corp. is under fire only because the family belongs to the Mormon church. Bob Witeck says this is unfair. “Their policies and practices have been good for a long time,” he told me. “This notion of targeting people because of their faith is deeply troubling.”

At first, I agreed. Anti-Mormon bias is no less troubling that anti-gay bias. Then I saw Milk, the wonderful new movie about the life of Harvey Milk, the first openly gay man elected to public office in America. Part of it is about a notorious California ballot proposal to ban gay teachers from schools that was defeated in the 1970s. Milk argues, persuasively, that singling out gays and lesbians for discrimination in any way, shape or form is simply un-American.

The broad issue raised by the backlash against Marriott is this: What role should CEOS and big companies play when confronted with controversial issues? Certainly they make themselves heard when it comes to the issues directly affecting them, like taxes, trade, labor and environmental laws, not to mention multibillion dollar bailouts. Ought they not take a stand on social issues, too? Indeed, some do—Microsoft endorsed a gay-rights measure in the state of Washington and Procter & Gamble donated money to a gay rights group to help defeat an anti-gay law in its hometown of Cincinnati, as I wrote in a FORTUNE story called Queer Inc. in 20006.

Bill Marriott responded to the boycott threats last month on his blog. “Neither I, nor the company, contributed to the campaign to pass Proposition 8,” he wrote. “We embrace all people as our customers, associates, owners and franchisees regardless of race, sex, gender identity or sexual orientation.” Later, he recorded a Thanksgiving message around the diversity theme, mentioning sexual orientation. Clearly the company is worried about the gay backlash.

My guess is that Bill Marriott, who is 76 and a political conservative, has come a long way on the issue of gay rights. But for all his talk about diversity, he has yet to take a position on gay marriage or Prop 8. He has no obligation to do so, but if you believe that gay marriage is a civil rights issue, just as interracial marriage was once a civil rights issue, silence or neutrality is unacceptable. On this point, Milk the movie and Milk the activist are unequivocal. Either you’re for us or against us, Harvey Milk would have said.

As one commenter to Bill Marriott’s blog wrote:

When it comes to gay issues, Marriott is conveniently a hotel chain that is welcoming and accepting of all travelers. When it comes to Mormon issues, Marriott is conveniently a company founded and led by members of the LDS church and fully supportive of church doctrine. Marriott can’t play it both ways. Through this posting, Bill Marriott is attempting to salvage Marriott’s reputation with a PR diversion. As Margaret Thatcher once said, “Standing in the middle of the road is very dangerous; you get knocked down by the traffic from both sides”.

Another disagreed:

It is amazing to me that in this great country, where we prize the precious freedoms of religion and speech, that a man can be criticized and attacked for his personal beliefs and religion. Mr. Marriott didn’t contribute to the Prop 8 campaign. His personal beliefs are irrelevant, because those are his PERSONAL beliefs… I’m just so saddened to see such hate and bigotry from a community who proclaims tolerance and love.

My own thoughts, which are subject to change: I’ve met Bill Marriott, who is an extraordinarily decent man, and I know from hearing from employees that Marriott is a gay-friendly company that values all of its workers. I know that it’s a lot to ask of the Marriott CEO to support gay marriage. But Prop 8 is a hateful and hurtful law, designed to take away the right of gay marriage granted by California courts. It was opposed by mainstream pols including President-elect Obama and Gov. Schwarzenegger.

Bill Marriot has the right to try to finesse the controversy. But gays and lesbians have the right to spend their money with companies that fully and openly support their cause.

A final thought: The future of the gay marriage issue could not be clearer—the younger you are, the more likely you are to support equality for gays in public and private life. Smart companies see where the world is going.