There is more here then the question of human dignity, although that is an essential part of the equation. More important is the basic question if sinfulness. This question is, who does sin hurt. God? The community? Others, not abstractly, but individually? Oneself?
While some say sin offends God, that is really not true. A God that can be altered by Its creatures would not be much of a god. Any such inference is creating God in our image.
Next, there is the community. Some sins are so strong that they rip the Church apart. While God cannot be moved by this, Her work is harder to accomplish. This also very much the case when a sin affects another person. It makes it harder for the one injured to connect with God.
The worst part of sin is how it effects the self. Grave sin twists the soul of the sinner, making it harder for them to find a true relationship with God.
This is why those who demonize our gay and lesbian brothers and sisters are so hard to reach. They simply do not want to let love for God, the Church, their LGBTQIA brothers and sisters into their hearts. It is the nature of sin to do this.
The same schema is necessary in dealing with the question if homosexuality. Gays and lesbians do not wish to be separated from the Church. It is up to us to teach them they do not have to be. They must have the courage to forgive the intolerance of their brothers and sisters in Christ and, if they lose heart and are dragged into sexual excess through promiscuity, we are there to help them heal their hearts, the hearts of any that they have cheapened and their own hearts, as promiscuity is ultimately a sin against the self. God created us all to find love. Love is in the giving, not the taking.
There is nothing more special for the Church, their families, their partner or themselves as finding a person to celebrate and be celebrated by. If they allow themselves to believe otherwise, it is easy to surrender to self-loathing. Loving another is a path to Heaven and cannot be a sin.
The Church sins against itself by not celebrating this love and inviting their families to do the same. It is time to boldly say this. Simply affirming the dignity of LGBTQIA Catholics is too mild. We must speak out in favor of their right to fully love another as God created them to. God is not an Ogre who throws hardships at whole groups of people to test their loyalty. God simply does not demand loyalty or obedience. God invites is to love, as God is love. The real courage is to accept a God of Love, not a god of certainty.