I have answered this in detail before, so I will simply gloss over the salient points.
The reason they are able to commit more towards socialist programs is that WE bear the burden of being the military policeman for the world. they spend 1/2 to 1/4 of the amount of GDP that we do on military because they know we will take care of the "messy business" wherever and whenever it arises.
You are misunderstanding the relevant statistic. They spend half as much per capita.
This has nothing to do with military spending. This has to do with achieving the efficiencies of a single payer system -- without a Rube Goldberg scheme of insurance companies, secondary insurance companies, 300 different yet curiously overlapping government programs, dual state/federal systems for Medicare, Medicaid, etc......
uber, those comics are fantastic.