Doug, that is the very same logic that blamed "communism" for the millions of deaths in the xUSSR. As I then argued against such accusations, and argue it now, a prudent thing to do is to analytically attribute individual effects to individual causes instead of demagogically attributing all effects to a single, most salient (from one's political point of view) cause.
Thus, we need to establish the net effect of US policies in specific geopolitical contexts while "controlling" for the effects of other factors.
That is to say, we need to assess what the situation would have happened without the US involvement (the counterfactual), and then compare it what did happened with the US involvement (the known facts). And we need to do it for every single involvement, not just the ones selected for ideological reasons. That means accounting for both, Chile and the Marshall Plan.
Secondly, even if we determine the negative impact through the above described analysis, we need to furtehr determine whether the said negative impact was intentional or simply an unforeseen consequence of a policy decision. There is a difference between, say, gassing 6 million people and implementing agrarian policies that later backfire and cause the death of millions (cf. the great faminie in Ireland). In the later case, we need also to determine whether the unforeseen consequences are due to gross negligence (i.e could have been easily foreseen if the decision makers were more diligent) or simply to bounded rationality (i.e. objective lack of knowledge).
In other words, we need to detrmine whether US policies knowingly created thugs where otherwise would have been virtuous leaders, or merely supported one thug over other thugs. Then we need to evaluate whether supporting "our thugs" was worse, better, or about the same for morally defensible policy outcomes.
I find it disingenuous that many self styled lefties advance caution and prudence when they rally to stop their political adversaries (e.g. US military lashing an attack), but lash out unrestrained accusations and verbal attacks (fortnunatekly they lack meaterial means to back these attacks) against their own pet Satans (e.g. the US establishment).
wojtek