And I think that’s why the parent used the word “indirectly”.
By supporting US industry you are indirectly supporting the US government and its actions, because those taking part in commerce in America pay taxes which support the US government. If you believe the US governments actions to be illegal or immoral then supporting US farmers would not offer a material difference to supporting Mexican farmers who themselves (it is alleged here without sources) are made to contribute towards the cartels.
Maybe that is what the parent meant, but that definition really dilutes the idea of responsible vs irresponsible choices to the point of meaninglessness, IMO.
Donating to a food bank lowers the taxpayer burden of paying for food, and American taxes fund cartels, so you're very indirectly funding cartels when you donate to a food bank.
I'm not sure that would influence any reasonable person's actions in any meaningful way, though.
“I don’t buy from Mexican farmers because they are extorted by cartels and forced to give them money which they in turn use to fund activities I don’t approve of”
Vs
“I don’t buy from American farmers because they are extorted by the government and forced to give them money which they in turn use to fund activities I don’t approve of”