I find this, in itself, a poor argument.
Many morally unthinkable actions would have positive effects.
For example, quick and sure execution for possession of marijuana would almost certainly reduce its use. But not too many people would be in favor of it for that reason.
Putting people to sleep when they reach 70 years of age would be highly beneficial to the economy in the long run.
And one can continue the list indefinitely. But we don’t do, or even consider doing, certain things because they are quite simply wrong, no matter how objectively beneficial.
Notwithstanding what I said above, someone with a strong personal belief in the rightness of a policy should not be trusted to do objective cost/benefit analysis.
Gruber obviously believes strongly in government-paid healthcare, and probably is strongly prochoice.
It is therefore wise to take analysis of the effects of these policies from him with a very large container of salt grains.