It's more about how the US handled the situation in a country with 3% of the population and the impact of that on either marginal voters or voters for whom this was a major issue.
In this case, it wasn't for lack of action. The US is actively funding one side's dominance and hindering others from helping the other side.
I think most people who are complaining about this are not expecting the US to be responsible for anything and would be pretty happy if the US just sat out.
