Why So Timid?

How come Democratic presidential candidates hesitate to say homosexuality isn't immoral:

Kenneth Sherrill, who teaches courses on gay politics at the City University of New York, said Obama and Clinton seemed "afraid to say homosexuality is not immoral." He added, "They are afraid of backlash. If you look at the polling data, you find a fairly large percentage of Americans think homosexuality is wrong even though they support equal rights."

It should also be said that in my experience pro-gay liberals, especially younger ones, tend to just assume that Democratic politicians' personal views on these issues are much more progressive than they're prepared to publicly admit. For all we know, however, Clinton and Obama actually are people with ambivalent (at best) views on the moral propriety of gay sex acts despite their support for equal rights. This is a very common view, especially among people who are somewhat older.