The Dean of Washington National Cathedral described homophobia as a sin Sunday, in remarks marking 15 years since the anti-gay killing of Matthew Shepard, but that come just days after a play on the young man’s death was reportedly marred by derogatory slurs.

College football players at the University of Mississippi have since apologized for their behavior while watching a performance of The Laramie Project last week, during which an actor in the production was allegedly called a “fag.”

On Sunday, in comments marking the 15-year anniversary of Shepard's death, the National Cathedral's Very Reverend Gary Hall said the church should have the courage to call homophobia and heterosexism a sin.

“Shaming people for whom they love is a sin,” he added.

The remarks came in a sermon attended by Shepard’s mother Judy and Jane Clementi, whose son Tyler jumped to his death from a New York bridge after a roommate at Rutgers University broadcast a video of him having a sexual encounter with another man.

After Hall’s address, both women took part in a panel discussion with the dean on the role of the church in supporting LGBT youth.

“We really have to stop making people feel like they’re broken or worthless or separated from god in any way,” Clementi said. “And we as Christian people really need to stop telling people that homosexuality is a sin.”

The discussion came just five days after the Ole Miss football team reportedly heckled performers in The Laramie Project.

The play retells the story of Shepard, who was tied to a fence, beaten and left to die in a remote area of Laramie, Wy. The 21-year-old was found alive after his ordeal, but died of his injuries five days later.

Eyewitnesses at the Oct. 1 performance described hearing some members of the audience using “hate speech” including a cast member being branded a “fag.”

Michael Barnett, the assistant theater chair, told the Associated Press that several students in the play told him audience members were disruptive and used "derogatory terms" for homosexuals during the show.

Ole Miss coach Hugh Freeze confirmed to the AP Thursday that football players were in the crowd, and that a group of them had apologized after the play.

"Several of the students said they did not feel the apology was genuine," Barnett said. "They seemed to feel that (the football players) didn't realize what it was that they were apologizing for."

After mounting pressure, Ole Miss Chancellor Dan Jones and athletic director Ross Bjork released a joint statement on Thursday afternoon, which read "we strongly condemn the behavior exhibited Tuesday night."

The statement said that the incident included freshman athletes from several different sports and it was "clear that some students badly misrepresented the culture of this university."

"As a member of the Ole Miss family, each of us has a responsibility to be accountable for our actions, and these individuals will be held accountable," the statement said. "Our investigation will determine the degree to which any and all students were involved."

Freeze tweeted on Thursday morning: "We certainly do not condone any actions that offend or hurt people in any way. We are working with all departments involved to find the facts."

The controversy led to several online calls for the university to suspend all the players involved in the incident.

Garrison Gibbons, an openly gay Ole Miss actor who was in the performance, said in a radio interview that he doesn’t want the players suspended, but believes they should wear gay pride patches on their uniforms for the remainder of the season.

“I’ve suggested that maybe they wear a pride ribbon on their helmets in the next few weeks for one of the games,” Gibbons said. “I think that would be a very symbolic message where the senior members, or the older members of the football team show the younger members of the football team that acted this way, you know, we are role models, we’re standing up, we support the community at Ole Miss and basically teaching them in a way that that’s the appropriate way to handle things.”

October is LGBTQ month. Ole Miss honored the month with a reception on campus Thursday night and will be hosting a Pride week celebration Oct. 7 – 11.

In a statement to Queerty, a blog focused on issues in the gay community, Shepard’s mother Judy said she was “disappointed” that the play was disrupted with anti-gay slurs.

“Using hate-filled words to interrupt a play about anti-gay hate is a sad irony that only reminds me of the work we at the Matthew Shepard Foundation and each of us as individuals must undertake to help stop hate,” she said.

President Barack Obama in 2009 signed a law named after Matthew Shepard that extended the federal hate crimes law to sexual orientation.

Despite the change in law, Shepard’s mother said Sunday that greater strides needed to be made towards stamping out homophobia.

“America prides itself on being the land of equal opportunity and intellectually and emotionally we all know that’s just not true here,” Shepard said during the panel discussion. “We have so much work left to do. Please don’t forget that.”