"Reducing Supply Hurts the Taliban in Particular."
Just the opposite. When military action or law enforcement reduces Afghan heroin exports, total trafficker revenues increase, but not everyone wins. Naturally, traffickers who are arrested or killed are worse off, but those who remain are in much better shape -- they capture a larger slice of a bigger pie.
In an ideal world, law enforcement would selectively target the nastiest of the nasty dealers, putting them at a competitive disadvantage and shifting market share toward traffickers who are merely bad in a common-criminal sense. The DEA and military understand this and try to selectively disrupt the traffickers who are linked most closely to the insurgency. But Afghanistan is not an ideal world. Even if coalition agents act sensibly on the available operational intelligence, that intelligence is far from perfect and there is good reason to fear that it can be systematically imperfect in perverse ways.
Afghan officials play a key role in obtaining and evaluating targeting information, for both cultural and legal reasons. But Afghanistan is one of the most corrupt states on Earth. Target selection is an exercise in discretion, and whenever officials exercise discretion, stakeholders have an incentive to sway those decisions with bribes or threats. Inasmuch as the most powerful insurgents are, almost by definition, the most skilled at bribing or intimidating officials, increased enforcement can specifically benefit those insurgents, even if the U.S. military and DEA do their best to avoid it.