1. The myopia is that they assume everything will be done EXACTLY as it has been done for the last 30 years, which causes the long trip times, the small living spaces, the lack of gravity. When you decide to not use the best technology to do the job, all sorts of bad secondary effects will happen.
My point is mostly that in these reports of "human problems in space" the reports specifically pick out the worst combination of chemical rockets, zero-g conditions and small habitat sizes, all of which are known to be problems, and all of which a long term mission would be avoiding because better solutions already exist that would fix these issues and confer many other benefits. So in essence, I would say this report would be better titled "Using the wrong tech for space missions is bad for the human body"
2. NASA started and then abandoned much of the tech. NERVA's has many successful tests on the ground and where ready for in space testing before the program was cancelled, so while there is still more work required, in no way is this a pie in the sky project, its just mechanical engineering. Expandable habitats are now being developed by Bigelow space craft and there are 2 successful platforms in orbit now, so it development seems well on its way for that project. Tethers or rotating spacecraft is the least developed of technology I have talked about, but the simple tether and counter-weight system is just that, simple so development of could easily be done in LEO