NASA uses Mars as an excuses to keep ISS

Here the argument is that NASA needs to spend money and time on their toy
space station.

http://www.smartbrief.com/news/aia/storyDetails.jsp?
issueid=4200843E-0CB2-4EC3-BA58-908C50BC821E&copyid=B513BE71-23AF-49F4-
A35B-731A8675A076

This is the best excuse that NASA can come up with to keep the ISS going.

Here's the problem with this thinking:

1) You're going to do radiation tests on scads of people to see if the
radiation is safe for a dozen people?! What's the logic in that?
2) The radiation data gathered would be trivial. The Russians should
already have radiation data from low earth orbit from their long duration
space flights, and we should have similar from our longest sky lab
missions.
3) The ISS is different than what Dr. Zubrin envisioned for a Mars
flight, which would be a tethered rotating system to provide artificial
gravity. So a trip to Mars would have some gravity and no protection from
radiation by the van allen belts. Other than being completely different,
I guess that's the same.