If we cancel the space program, we might as well spend the money on cheap booze and cheaper hookers, because we will have totally fucked ourselves, and doomed our race to destruction. What does everyone think they're doing up there? We just spend billions of dollars to send people up there to sit around and look out the window at all the pretty stars? This planet has a lot of problems, yes. But ignoring the bigger picture is the last thing we need to do. We can spend all of our resources taking care of all the problems down here, making sure everyone is taken care of, return the environment to a perfectly healthy state, etc etc. It doesn't change the fact that the Earth is still a time bomb, and the clock is ticking.
With the tragedy with the shuttle, all of the sudden everyone cares about this subject (which they probably never gave half a thought to before), so it's being knit-picked to death. That will change in time (if we keep the program going, that is). A lot of people will be changing their tune when we find a bacteria or a fungus or something under the crust of Mars or something that doesn't exist on this planet that creates a cure for cancer, or something of the like. Chances are everyone here already knows somebody taking a medication/whatever for a condition they have that was developed in space, because the proper conditions for the research cannot be found on Earth.