A famous podcast host recently asked a Catholic commentator why he opposed homosexual marriage when it did not personally injure him in any way. Unfortunately, the Catholic commentator was unable to provide a very memorable response. Admittedly, it can sometimes be tough to answer these types of questions when put on the spot, especially in front of a massive audience, but below is a suggested response that may perhaps be of some help.
First, what a strange question this is to ask – as if the morality of an action depended upon the degree of hurt it caused an uninvolved individual. It may not personally injure me if you rob a bank or blow up a building, but of course we agree those things are wrong. So there has to be another standard by which morality is measured.
Secondly, it does cause a great deal of personal injury when a mockery is made of the divine institution of marriage. There is of course the obvious fact that the society which permits and even embraces such sins is crying to heaven for vengeance, and as a member of that society I am very fearful of the just wrath that God must impose upon our society. The perversion of marriage also injures me in other ways. I must now be extra vigilant in teaching my children the truth of the divine institution of marriage. I must constantly be on my guard to see that my children do not develop faulty ideas concerning marriage. I must now live in a society which devalues a holy institution and necessarily begins to devalue all morality. I must live surrounded by chaos and disorder. I could go on, but to dwell on this point would be fruitless.
There is really only one answer that must be given to this question, and that is simply that these terrible sins offend Almighty God. Our Creator, our Redeemer, our Savior, our Father, our Brother, our most beloved Friend, the only Love of our souls is terribly, incomprehensibly offended by these horrible sins. If we have any love for Him we must oppose these crimes against Him. It should break our hearts to see the Sacred Heart so mistreated and abused. We should stop at nothing, out of love for Him, to do all in our power to see that these horrible sins are completely eradicated from society. The only reason they exist is because our society does not love God. We must begin to change that by seeing to it that we personally love Him, and then we must do our very best to teach others to love Him too.
I love Thee, Jesus, my love, and I am heartily sorry for ever having offended Thee. Please forgive us from our sins according to Thy great mercy, which is above all Thy works. Most Sacred Heart of Jesus, have mercy on us!
TomNaegeleBlogs 
Such true, horrific, beautiful sentiments, Thomas. And because it’s our role as a Catholic to help all souls reach Heaven, these abominations carried out by others injure us deeply: They prohibit us from fulling our joy, our duty, our calling to serve God by loving Him through loving our neighbors enough to share the hope of Heaven with them. Sadly, their ears are closed and their eyes are veiled. Indeed, their influence on children is their worst offense of all. Godspeed, good man! Thank you for posting.
As if there was any longer any question of whether or not Sr. Lucy was correct that the final battle would be over marriage and the family.
I can point out another way society’s ruined definition of “marriage” affects me, even though I never had the chance to marry: my sister and her live-in bf are “marrying” before a justice-of-the-peace, complete with Wiccan “handfasting.” I obviously can’t go. And this is going to cost me Everything. In all likelihood, my father will be the only relative who will ever speak to me again. I anticipate that my mother will go to her grave not speaking to me. All because I cannot break God’s law, but the fact that I’m even in this position, that my baby sister is even in this position, is because of the total breakdown of marriage.