because the heteros aren’t doing a good job at it.
In addition to other good posts, you can approach it in a number of ways. One is to simply say, if, hypothetically, gay so-called marriages would result in less divorce than heterosexual marriages (which it doesn’t–we’re talking hypothetical here), that still doesn’t change the fact that a homosexual union CANNOT ontologically be a marriage. It is still impossible. A triangle cannot be a rectangle even if it really, really wants to be.
Additionally, marriage collectively is indeed a sick institution in this age, however, approving gay so-called marriage is not a solution or a help to that problem whatsoever. But what you can point out are some of the causes of that problem, such as no-fault divorce, contraception, abortion, fornication, hypersexualization of media, etc… The Church has always been opposed to these. In the 60s, the Church was against the pill, which has led to the objectification of women, amongst other problems. Pope Paul VI is
now known for his accurate predictions back in the 1960s that have come to fruition.
In every case, society gave its seal of approval to a matter regarding sexuality or the genders that the Church warned against approving. In every case, the Church has proven prophetic and correct. And here is the secular culture again, demanding that another perversion of relations between genders be certified, when it is the secular culture’s previous demands that have led to the corrosion of marriage in the first place. And again the Church warns against the perversion. And time will, once again, vindicate the Church if this perversion is certified, and the same secular spirit will turn a blind eye to the Church’s wisdom.