The rest of your quote is:
Patrick R. Chai and Alan W. Wilhite of the Georgia Institute of Technology presented a study earlier this year estimating that depot tanks would lose about $12 million worth of propellant per month in low Earth orbit if protected only with passive insulation.
I don't think anyone has ever suggested storing liquid hydrogen in a passively insulated tank in low orbit.
ETA: It goes on to say:
The cost savings could be leveraged to other initiatives, such as developing a lunar lander or a nuclear propulsion module, both of which –in theory- would be unfunded with the SLS option
They're not unfunded in theory, they're unfunded in the NASA budget. Without some kind of payload <voice deep and resonant with lots of reverb> "exploring deep space" </voice> is the same as sitting in LEO, but with vastly more radiation and no view. NASA is talking about sending the Orion on a trip around the moon, but what is the point of that? We've already flown around the moon thousands of times. With no lander, there's no purpose to flying around the moon, except that the purpose of flying around the moon is to justify burning all the fuel for the SLS without a lander and with nowhere in particular to go.