There is a large contingent of people who disapprove of gay marriage, and a smaller group who disapprove of gays in general. This latter position seems particularly ludicrous, given that gays can't help but be gay. Many liberal supporters of gay marriage are vociferous in their disapproval of people who disapprove of gay marriage.
And it does seem reasonable that if two human beings really love each other -- if they're soulmates -- it shouldn't make any difference that both have penises or vaginas. (As in, "I fell in love with a person who just happens to be a man.")
Yet many of those same liberals disapprove of another type of love: that between an older man and a younger woman. I've heard many liberal middle-aged women who approve of gay marriage speak absolutely scathingly about older men who date younger women. But why is that wrong? After all, if two people are soulmates, what difference does it make if one has more wrinkles than the other? What kind of person would be so narrow-minded as to divide people up along such superficial lines?
(To be fair, I've never heard a liberal woman suggest that marriage between older men and younger women be made illegal, which is perhaps the more appropriate comparison here; but at the same time, I've certainly never heard one speak approvingly of such a union.)
Even more ironic, many of those with whom the concept of a "dirty old man" has great currency take a "You go girl" attitude towards cougars.
Such selective disapproval, as always, indicates a double standard.