In this sense, he said, the Church needs to give more visibility to the people with same-sex attraction who have opted to live celibate lives. He pointed to Courage International, an organization that counsels individuals with same-sex attraction who chose to live according to Church teaching.
"We're just sitting over here quietly abiding by every word of the Catholic Church and finding it to be the recipe for happiness, and we don't get much attention," Mattson said.
The people who have tried living the LGBT lifestyle and "found it empty," he said, "want to share what we found with the LGBT community and invite them into the full community of the family of God."
Mattson said that while he has been called "crazy" or "internally homophobic" for speaking out, "I just have to laugh that off."
Mattson said those who describe Catholicism as "homophobic" usually imply that the Church is somehow a "hateful place" with no room for people with same-sex attraction.
However, "the opposite is exactly the case for me. I have never felt more welcomed in my life than in the arms of Holy Mother Church."
"It's the most welcoming place," he said, "and it's sad if people want to use the language of the world to say that, to use that word and say that the Church doesn't have a place or that it isn't welcoming. For me, it's been the exact opposite."
When asked by a priest in the audience how pastors ought to react to people who come to them and confide having same-sex attraction and feelings, Mattson stressed the importance of creating "an environment that is safe," since many of these people already carry many wounds.
The fact that a person feels they can open up to begin with is a positive sign, he said, explaining that most people with same-sex attraction are afraid that "they will be treated with disgust" if they open up about it, so knowing they have a safe space to talk is key.
Mattson also mentioned Pope Francis, telling CNA Pope Francis has been clear about the Church's teaching, and explaining his belief that Francis' message is often manipulated by the media "to serve their own agenda."
Mattson said he always remembers the pope's comments on his flight back from Rio de Janeiro in 2013 when he said that he is "a son of the Church."
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"If you really look at what he's said, he's been very clear about same-sex marriage over the years, he's been very clear that chastity is an important virtue," he added.
"He's said he's a son of the Church and I'm confident in that," Mattson said, and voiced his hope that one day he would be able to meet the pope and tell him "how the Church has been a mother to me and has guided me to happiness and freedom."
Mattson also expressed support for the view that sexuality doesn't define a person's life, and stressed that using labels such as "gay" or "straight" reduce a person to their sexuality, since in the end everyone is ultimately a child of God.
"The truth is that my sexual identity is (that of) a man, just like Adam, just like Abraham, David, just like every other man that has walked the face of the earth, I'm not a different sort of sexual person than they were," he told journalists.
"The Church's teaching is that you are identified as a beloved son of God, that has been the experience for me."