I will add that the State department under Hilary Clinton was very vocal about using social media like Twitter and Facebook to facilitate the Arab spring movement. I suspect this is the reasoning behind the funding. The US government hands out money to many projects and companies. I feel much better about this than say the money that was given to the social media platforms. But, honestly I don't feel good about any of it.

The motives aren't what counts though. The code and security are. It isn't hard to monitor an OS to see if it is phoning home on your activities. I'd be shocked if they were able to pull that off without privacy activists and developers spotting it. Far more likely that Apple or Microsoft are partnering with the gov than Tails.