How Do Conservatives Explain Negative American Exceptionalism?

Over at the Washington Monthly, Keith Humphreys put up a chart comparing various countries along the axes of homicide rates and incarcerations rates.

Ideally, you'd want to be a country that has low homicide rates and low incarceration rates (Norway, Germany). Countries that have low murder rates, but get there by locking everyone up, are despotic (Iran). Countries that have low incarceration rates but high homicide rates are lawless (Mexico). And the finally, countries which throw everyone into prison but still have high crime rates are "disastrous", and of course, the U.S. of A. falls decisively into this category.

(Kevin Drum thinks violent crime rates are more useful than homicide rates for this sort of illustrations, which reshuffles some of the countries, but not in a way relevant to our purposes since the United States remains a clear disaster.)

I've long been curious how conservatives explain this sort of American exceptionalism -- metrics where America just clearly and unambiguously is far worse than nearly any other peer nation. Why, under the conservative telling, are we so bad at this compared to other countries?

Liberals don't have too much trouble with this problem -- partially because we're less wedded to chest-thumping about "greatest nation on Earth", more saliently because we have an easy explanation (guns + racism) ready to roll. But of course conservatives aren't going to be fans of that explanation. So what do they go with? It can't be "soft on crime" -- again, we're clearly "tougher on crime" than most peer nations (perhaps some "reforms" in that direction could push us into the "despotic" quadrant alongside Iran -- what a cheery thought -- but it doesn't seem to work as an argument). And I can't say I'm drawing much when I try to think about how they purport to explain this phenomenon. Do they just sit in denial of it?