Why choose to cut space exploration? Surely there are a myriad of more "worthy" targets to cut in favour of social programs?

For example: I don't see the point of a manned mission to mars at this point in time. We clearly wouldn't be able to settle a colony there. Until it becomes so cheap/easy/efficient, we're better of diverting resources elsewhere.

I am by no means categorically opposed to space exploration or research.