If you'd read the older thread, you'd notice that the intervention by air is not as simple as many would like to think. Even the usual "jam the radio station" mission would require more aircraft, support, and overflight permissions than many assume.
And, of course, you've ignored the $64 question: What happens when the radio station is no longer jammed and the intervention troops go home?
Yeah, problem is the United States has decent relations with a lot of the people who can give them these permissions and in particular the president of Uganda would have every reason to let the US run a mission against Bagosara and the Interahamwe that would involve the blocking of RTLM.
The difficult part comes in assuring something after the last troops leave, the RPF would probably have to be a part of this. At the start of the genocide there was a coordinated effort made on the part of the Hutu extremists to kill moderate Hutu politicians who would have either supported the Arusha Accords (which involved a power-sharing deal between Habyarimana's party and the RPF), disagreed with the notion of extermination of the Tutsis or both. CalBear's point regarding the Hutus is important here, it does bear mentioning that Tutsis were not the only victims of the Rwandan Genocide, only the most well known, moderate Hutus who didn't play along with the Interahamwe or the government were killed, and a whole lot of people used the chaos of the genocide to settle old scores not of an ethnic character or just to take advantage (as in I kill my neighbor, say he was a moderate, and take all his nice stuff). In the end, the last two groups standing that were organized were Bagosara and the extremists and the RPF, any hope for ending the genocide is not going to come from supporting the ones who are doing it so that task falls to the RPF.
People are assuming that the RPF would really go any further than it did
in the immediate aftermath of a genocide that was 75% successful that is to say tragic incidences of Tutsi-on-Hutu violence inflicted by RPF soldiers with links back to high command... questionable in most cases. A lot of Hutus left Rwanda fearing exactly this, and it lead to the Great Lakes Refugee Crisis we have today.
Diplomatically China will be as annoyed as it was when NATO bombed the Chinese embassy (the one that was letting the Serb paramilitaries use their communications for their own purposes... oops) but it will drop the issue given that relations with the US are more important than arms trade with Bagosara. Any sort of US intervention will probably uncover some degree of evidence that France was helping the
genocidaires to the point where French soldiers were actually teaching Hutu militias in the pre-genocide days how to cut open the stomach of a dead Tutsi and throw them in the water so that they would sink to the bottom.