While it is an enormous problem, possibly the most significant, we know how to shield against radiation, but it's going to take mass in the form of hydrogen-rich molecules like water or polyethylene (as examples). To solve that problem we are either going to have to make launches a lot cheaper, or figure out how to do it all in orbit.
It's at the edge of our technological capacity to produce such a spacecraft now, so the barrier is economic. That's a massive barrier, but in theory we definitely could, if we put a significant percentage of GDP of the wealthiest nations towards the project, produce a spacecraft that keep astronauts alive and relatively protected from ionizing radiation both on the journey and while on Mars.
As to your general assholery, I guess everyone has to have an outlet, though why Slashdot is a bit mysterious.