We recently read a great article detailing why it is misleading to compare US murder rates with those of so-called "developed countries". First of all, it is wrong to use all firearm deaths as a comparison subject, as this figure does not represent violence done by an assailant to another, but includes accidental shootings and suicides. Let's be honest, if a person is going to take their life and they don't have access to a firearm, they can (and likely will) use a wide number of readily available mechanisms to accomplish their goal, from knives, ropes, prescription drugs, cars, trains, etc.
Secondly, the left's use of "developed countries" to compare to is also misleading on two fronts. The "developed countries" often compared to are almost always hand picked to paint the US in a bad light. The left doesn't use all developed countries in their comparison, but only those that will support their pre-determined conclusion.