A pro-gay rights Republican group contends that it has been barred from sponsorship of next week’s high-profile Conservative Political Action Conference, or CPAC, because of the sexuality of some of its members. The group’s executive director dismissed procedural reasons cited by organizers.

Gregory Angelo said that for the third year in a row Log Cabin Republicans was being denied participation in the event, which is run by the American Conservative Union (ACU), “because we might support marriage equality and we might have some members who identify as gay”.

CPAC 2015 takes place in Washington DC from 25 to 28 February. Speakers will include senators and 2016 hopefuls Ted Cruz and Rand Paul, new Iowa senator Joni Ernst and the real-estate mogul and reality TV star Donald Trump.

“Gay people have always been welcome as attendees at CPAC,” Angelo said, “but that’s not something that should necessarily be celebrated – it’s something we should expect in 2015.

“The challenge has always been any formal participation, explicit sponsorship, by any organization that has a definite connection to the gay community.”

But the ACU, which organizes the event at which presidential hopefuls often seek to appeal to the GOP base, maintains that the Log Cabin Republicans simply never applied. A spokesman for the ACU flatly denied any bias against gay people, and provided a statement by chairman Matt Schlapp.

“We do not bar any groups or individuals based on sexual orientation,” Schlapp said. “The Log Cabin Republicans have not applied to be co-sponsors of CPAC 2015. Had they applied, they would have been subjected to the same review as every other application.”

Angelo did not dispute that his group did not fill out the form, but said the ACU was simply using the paperwork as an excuse.

“That’s a canard; the reasons for our exclusion keep changing,” he said. “If we had gone out and filled out some online form, I’m sure the ACU would be telling us we didn’t use the right web browser.”

Angelo said he had for months personally petitioned for sponsorship through Schlapp, other ACU officials and surrogates, but that they had failed to respond.

“A week ago I saw one face-to-face, put a business card in his hand, asked him to call me about CPAC, and his response to me face-to-face was his response in email – essentially none,” he said.

Schlapp also said that the group needs “to start advocating for conservative policy solutions and siding with conservative candidates in primaries”, a demand that Angelo found absurd. He said the Log Cabin Republicans could go “toe-to-toe” with any other conservative group and listed the group’s policy positions, which support gun rights, fracking and repeal of the president’s healthcare law.

About primary candidates, Angelo said: “If we were to change our bylaws and start siding with candidates, the ACU would probably come back with something else.

“The continuing moving of the goalpost seems to be symptomatic of some element of ACU leadership that does not believe that organizations that advocate, in any capacity, for gay rights can be part of the conservative movement.”

Angelo, who plans to attend CPAC, also said he found it ironic that the event will award a freedom-of-speech prize to Phil Robertson, the Duck Dynasty reality TV star who said in 2013 that homosexuality is “not logical” and that gay people “won’t inherit the kingdom of God”.

The irony, Angelo said, is that the Log Cabin Republicans “were one of the only conservative organizations standing up for Phil Robertson and freedom of speech when organizations did not dare. So if anyone should be celebrated for a freedom-of-speech award, it should be us.”