Marriage needs positive reinforcement, and mainly from other married couples. That’s not to say that the bishops and clergy don’t have a role as witnesses to the liturgical celebration, or as spiritual directors.
Archbishop Dolan neglects the history of gay rights. Same-sex unions accomplish in one legal step all the reasonable expectations (and perhaps a few others) that unmarried couples seek. Visiting sick loved ones in the hospital, sharing financial resources, insurance considerations, visitation of children, adoption: none of them of themselves are immoral. The sticking point for Archbishop Dolan’s tack is that he doesn’t address the root “immorality” of the situation. The ultimate “attack” on marriage is extra-marital sex. The man is probably unwilling to tackle that point. It leaves his outrage on DOMA rather weak.
Instead of the hermeneutic of subtraction, the archbishop could instead consider bolstering the Marriage Encounter Movement, strengthening the Church’s relationship with engaged couples, possibly through mentoring by experienced couples. Then there would be the advantage of integrating unchurched couples into parish life. Or developing initiatives to encourage adoption.
Please, Archbishop Dolan, do the work you can do where you can do it. Leave the legal stuff for the realm of the laity.