Now, I don't necessarily agree with these space travel enthusiasts, but let us suppose for a moment that I supported their goals, at least in the long run. It doesn't necessarily follow that I'd consider the best way to advance their cause right now to be continued launching of manned missions at all costs. After all, any such efforts today would involve only known, well-understood technology, and are more likely to lose public support, by failing spectacularly, than to garner votes by serving as a platform for performing the standard, tired "stupid weightless astronaut tricks" in front of a TV camera.
Real progress towards space travel would require first solving some of the daunting problems that make long-term human habitation of space so difficult. Here, for example, off the top of my head, are three avenues of scientific research, enormous progress in each of which is absolutely essential for any large-scale manned space travel to be possible. Moreover, they can all be pursued today without the cost and risk of actual manned space missions, and they also possess enormous potential for beneficial technological spin-offs quite apart from their space travel applications.
I predict that if these (and a few other) fundamental research problems are successfully addressed, then the advances in "core" space travel technology--rockets, orbital vehicles, and so on--needed to make space stations, moon bases and even mars missions possible will be a relatively simple afterthought.