Because it has warped American understanding of marriage and thus had a bearing on the public conversation and legal developments.
find a liberal rag to read
I am the one arguing for an understanding of marriage that's life-long, fruitful, and heterosexual. This is real marriage, God-given, revealed in nature, and honored by the Judeo-Christian tradition. You do realize that you're the liberal in this conversation?
I'm not arguing with you on that, and you know it. You argued that, "Rush’s disordered view of marriage is well within the American mainstream, which makes it inevitable that this country will not — cannot — see anything wrong with same sex marriage.
This is where you take a liberal bent, you know well that this holds true ONLY in a minority of states that are liberal. The majority of states do NOT approve of same sex marriage - it is only passing by judicial fiat in any conservative state. If the majority of states approved of same sex marriage, then the people of those states would have passed legislation to make it so.
Your position that truth cannot come from a hypocrite is also a liberal position. We are all with shortcomings and no one can speak truth without admitting they have faults of their own. Therefore, taking the position that a hypocrite cannot speak the truth is a red herring in the argument for the truth; a typical liberal ploy.
Your lack of faith in the American public only serves the cause of liberalism. Grow a spine and fight for what the truth is and what is right instead of ragging on the US.