Madison, I think some people would say "Cool, tell me something I don't know", others wouldn't care because they're too busy juggling with Family/Work/Bills to allow the luxury of thinking about Aliens or the Philosophical/Religious ramifications of their existence.
Another group would chalk this up to being a lie, meant to disrupt and destroy their political and/or religious beliefs, and will thus believe that CONSPIRACY.GOV is targetting them. This could easily cause a "radical" element to exist within the various "fundamentalist" or "conservative" faiths, due to the static systems within which in turn would lead the .GOV to Actually target those folks.
Some folks may see Aliens as actually existing as "Evil/ bringers of Cataclysm" and start their own sects. And attempt battling them, for sake of God/Allah/Gaia.
Luckily, most faiths don't have Humanities exclusiveness explicitly revealed in Scripture, only as applied doctrine, which may be modified, and Aliens may be seen as parallel and neither inferior, or "evil",.By Theologians and more mainstream religious bodies.
The Global MilitaryIndustrialComplex would see it as an opportunity to both steal technology, and find a new enemy to prepare war/profit against.
This would definitely bring about some sort of Homogenization as far as political stuff goes. And crackdowns on dissent. Circumstances would "require it". 
I think they're coming for our Chocolate, myself.
