The "reaction" I don't think is truly from John Kerry's mentioning the fact that the Cheney's have a gay daughter, or even mentioning her by name. Given that the VP is trying to pretend he's against a federal amendment to ban gay marriage even though the official line by the administration is that they're in favor of such an amendment, on the grounds that he believes that the states should have the right to make marriage laws -- also in contradiction to the official position of his party -- when he invokes his gay daughter, it's just part of the discourse on the issue. Cheney and Edwards had a polite exchange on the subject during the VP debate, and Cheney had his chance to express outrage at that point and punted. Kerry certainly said nothing that could be considered offensive when taken at either the face value or the context of the debate -- in other words, without extreme distortion or spin.
Let's get down to brass tacks. It's the word "lesbian" that's at the heart of the matter. It's still considered salacious -- by people who don't get exposed to it a lot, largely elderly and conservative folks who tend to invoke it never. But that's not really what's at play here. In point of fact, I suspect most conservative males consider lesbianism to be kinda hot. Why else would it be such a big part of the porno industry? I won't pretend to get into the psychology of the matter, but "lesbian" to a straight male isn't a disgusting word so much as a suggestive one.
"Sodomy", on the other hand, is, and it's Sodomy that's talked about in the bible. There is only a single veiled and ambiguous reference to woman-on-woman sex in the bible, and even that is in one of Paul's epistles to the Romans, written well after the new and old testaments. I again won't pretend to know why the ancients were so hell-fired concerned about butt sex, although there's plenty in the anthropological literature about contexts for tolerance or intolerance of homosexuality based on clan moires. But the bottom line here is that when you hear a Christian conservative cite the bible as the source of the imprecation against homosexuality, we're talking about one forbidden practice associated with man on man homosexuality. Not lesbianism.
I have a hard time grokking out whether the use of the "L" word was a calculated tactic by the Kerry campaign. I think Kerry just used the word because it's gentler than the clinical "homosexual", and gays and lesbians call themselves gays and lesbians, and more accurate than "sexual orientation" in context, since the essence of Bob Schieffer's question was whether each candidate thought homosexuality was a matter of voluntary orientation or genetic hard-wiring. Kerry said he thought God made us all the way we are by nature, and Bush said he didn't know.
So this is what the "controversy" stems from, above and beyond the use of political spin by either the Dems or Reps. The outraged conservative is secretly ashamed that they're secretly aroused by the idea of two women getting it on, but they're not at all unhappy with being able to bash the idea of sodomy because they're genuinely disgusted by it. It's all part of the insecurity about sexuality which is brought on by believing a weird hodge-podge of dogma overlaid on the bible by cultural norms and prescriptivism.
Insofar as there is insecurity about lesbians, I think it's the idea that women can do just fine without men. They can have great sex, even have and raise children without permission (unlike gay men) from the state. (If the religious right gets full control over state governments, you can bet there will be laws introduced making it illegal to use sperm from a sperm bank unless the withdrawer is a married woman -- married to a man, that is.) If your worldview is patriarchal, there's no more literal a threat to your very existence, or at least your power.
This is what the left (and mainstream) has to understand about the hyperreaction to issues surrounding homosexuality. It's not just "live and let live"; these people are genuinely concerned about the very existence of homosexuality, because where there are normal, well-adjusted gay people there's the hint that families can in fact have different power structures and organizations and so forth. That in turn must inevitably suggest that religious literalism is philosophically and logically incorrect. They believe the idea of a "normal" gay person is an affront to their entire belief system. It has nothing to do with actual property and legal rights inherent in marriage.
And in turn, the pandering by the Republican party to the religious right on this subject is largely one of playing to the psychological basis, not the religious one. Even the Republicans can't come right out and endorse the bible as their basic political text. But they can use the art of the unspoken, of the sin that dare not be named, to play on the psychological fears of people around their own sexuality and family structure.
That's why they seem more up in arms about the word "Lesbian" than the issue at hand. It's suggestive in a way which I think they hope to play to a base on which secret fears -- and desires -- cloud logical thinking, like most emotional appeals cloud logical thinking.