Yes, that's a reasonable dissembled description of the scam they try to pull. They think we ought to just allow people to lie there and die in the gutters so as to teach them all a valuable and permanent lesson in the efficacy of social-Darwinism.
An interesting view of things: libertarians are culpable for being "socially darwinistic", while simultaneously discouraging personal responsibility. I'm not quite sure how that's physically possible.
In the above, your "we" makes no distinction between government and citizen. You ought to examine that a bit. Especially since compassion is not a virtue imposed by laws. Libertarians would not dissolve the Red Cross, Salvation Army, The March of Dimes, The American Cancer Society, or any of the innumerable private religious charities that do a better job of caring for the truly needy than the government does. Incidentally, such organizations hover around 78% efficiency compared to the government's 26%. And their coffers would only swell if people were allowed to keep more of their income. I think 9/11 showed that.
Don't confuse the libertarian (or constitutionalist) approach to federalism with "lack of compassion." It's the same argument the left uses against the right every day. When you engage in it, you make tacit admissions that that left is correct in its methods - with the only implied caveat being that they "go too far."
As with most of these discussions, the pivotal question lies not in what should be done, but who decides what is to be done, and how.