Californians Against Hate officially kicked off a boycott against all three of Doug Manchester’s hotels on July 18 at its March on Manchester: A Demonstration and Rally Against Hate.

Additionally, the same-sex marriage advocates demanded Friday that Hyatt Hotels Corp. end its relationship with a business partner who is financially backing a California ballot initiative to ban same-sex marriage.

Picketers outside the Manchester Grand Hyatt waved rainbow banners and signs reading “The ‘Hyatt’ of Hypocrisy” to protest owner Doug Manchester’s $125,000 donation to a group backing the November ballot measure.

If it passes, the amendment, known as Proposition 8, would overrule the Supreme Court decision that legalized same-sex marriage in the state as of June 16.

“(Hyatt) put so much money into advertising this hotel in gay magazines, and it’s a huge slap in the face,” said newlywed Manuel Munoz, 33, who was in town from Rancho Cucamonga honeymooning with husband Ed Alberson. Munoz was staying at a nearby Sheraton.

Hyatt said it took no position on Manchester’s contributions to the marriage initiative. The company manages the 1,625-room waterfront hotel on behalf of Manchester’s development company, Manchester Financial Group.

“It’s a personal decision of Mr. Manchester’s that doesn’t involve Hyatt,” said Hyatt spokeswoman Lori Alexander, who watched the sidewalk protest from the steps of the hotel. “His name is on the door, but it’s not the views of Hyatt.”

Manchester, who goes by the nickname “Papa,” did not return a message seeking comment at his office. He has said that he welcomes gay and lesbian guests at his properties but believes that marriage should be reserved for heterosexual couples, in accordance with his Catholic beliefs.

The protest came ahead of the city’s Pride celebration last weekend, which attracted 150,000 visitors. Alexander said the Manchester Grand Hyatt is sold out.

Despite those claims, however, a look at the hotel’s Web site and a call to the hotel on Saturday revealed that there were plenty of rooms available in every category during the busy Pride weekend in San Diego. And activists said Hyatt couldn’t afford to hold itself at arm’s length.

“Hyatt is involved with someone who is giving a lot of money to a campaign to take away our rights,” said Cleve Jones, a longtime gay-rights activist and organizer for Unite Here, a labor union representing hotel workers. “They need to decide what side they’re on.”

Counter-protesters gathered opposite the hotel driveway to voice their opposition to “Adam and Steve” weddings.

“We don’t hate anyone who has a same-sex attraction but we can’t let them redefine marriage for the rest of us,” said pro-life activist Vita La Fond, 59, who explained to passersby that she was holding a banner to do her part on behalf of traditional families.

Brian Brown, California director for the National Organization for Marriage, defended Manchester’s right to contribute to the initiative campaign.

“People should be able to stand up and contribute for the common-sense idea of marriage,” Brown said.

Manchester’s company also owns the Grand Del Mar golf resort in the seaside La Jolla area about 15 miles north of Downtown.