Godwin's Law anybody?
That is a garbage example anyway even though it's a blatant violation of Godwin's Law.
IG Farben produced Zyklon-B which was a pesticide. It was invented in the 1920s, long before the Nazis came into power. I would have no problem with IG Farben having a government contract to produce Zyklon B.
The government is the one that perverted its use to get rid of what they deemed human pests.
Did IG Farben know? Yeah, probably. And yes I have a problem with them selling the product if they knew that was the end use.
And if the government outsourced a contract to run the camps to a private business (say, IG Farben Government Services Division), I wouldn't want to patronize them.
But there is one little flaw in their argument:
I would have a CHOICE to patronize Costco, Sam's Club, BJ's, or wherever.
I wouldn't have a CHOICE on which company's death camp to be murdered in.
But feel free to try again with another argument that's not so flawed.