I guess I'd object to the USAF and Navy assets as well on libertarian grounds, but it just seems to me that USCG has about as much a duty to Antarctica, as the NYPD would have to Antarctica. Libertarian stuff aside, USCG is supposed to guard the US coast.
I'll admit I've never given much thought to the market mechanisms in place to supply arctic oil drilling operations or antarctic research operations... I just figured that sufficient free market resources existed to accomplish these objectives and were probably operated by the major stakeholders in ocean drilling and large scale construction/salvage concerns. Between BP, Haliburton, Maersk, Exxon and all the other major efforts out there I assumed most ice breaker ships were capitalist operations.