David Bahati, the bill's main sponsor, is (according to Jeff Sharlet) a member of the Family, a fundamentalist group most famous for evangelizing to American politicians. It counts North Carolina representatives Heath Shuler and Mike McIntyre (both Democrats) among its members, as well as anti-abortion amendment guy Bart Stupak. The Family has also had connections with Museveni in the past. It's unclear whether the Americans who run the Family are supporting Museveni and Bahati in their ridiculousness; in fact, I doubt it. It is, however, worth noting that the ideologies that support this insane bill are influenced by American conservative evangelicalism, and as such, it falls to American conservative evangelicals to denounce the legislation since doing so might actually have an effect.
I currently have no idea whether or not most of the American conservative evangelical movement's leaders have even been confronted with this legislation and forced to take a stand on it. One conservative evangelical leader has, though: Saddleback Church pastor Rick Warren. When asked about the law - Warren is fairly involved in Uganda - he replied in a disappointing manner that generally implies his desire to remain neutral on the issue:
The fundamental dignity of every person, our right to be free, and the freedom to make moral choices are gifts endowed by God, our creator. However, it is not my personal calling as a pastor in America to comment or interfere in the political process of other nations.You can't comment? A mass murder is about to take place in a country you're deeply involved in and you can't be bothered to comment about it? Indifference in the face of mass murder is a sin, of course, but it's not as bad as tacit approval. If Warren had been actively opposed to other mass murders overseas but not this one, then we'd have an issue.
Oh, wait, what's that, Twitter?
Mmmhmmm. So it's horrible, HORRIBLE, that Christians are being killed overseas*, but when it's happening to gays? Can't comment. I now have no respect for Rick Warren. This attitude of "I'll only comment on genocide committed against my particular identity group" is dangerous and what enables genocides to occur.
*Of course, I am just as opposed to people killing Christians because they're Christian as I am to people killing gays because they're gay. Warren's right on the spirit of this tweet - genocide committed against Christians doesn't get anywhere near the press it deserves in this country outside of evangelical circles. However, he's wrong on the substance - many non-Christian human rights groups speak out against such killings daily. Governments that encourage the slaughter of Christians should be criticized too, and I doubt Warren would have any qualms about doing so.