It's just talk, though.
You know, with a fusion rocket, which ejects particles with 10 million times the energy of the best chemical rockets (and these things were designed under U.S. government contracts in the '60s but never built, although two extremely powerful fission rockets were built and tested on the ground, ), a rocket producing 1-g acceleration that accelerates halfway to Mars then decelerates at 1 g from the halfway point can make it to Mars in just two days, reducing radiation exposure during the trip a hundredfold, while providing normal gravity the whole way. To save money, okay, scale it back and take a week to get there. But six months in a tin can coasting through space is enough to turn astronauts into homicidal maniacs unless they travel in induced comas. And even if they make it, what about the trip back?
But yeah, we already knew that much exposure to radiation was unreasonable. And what about radiation on Mars once they get there?