If a company refuses, they are making a decision (more of a gamble). Corporations will almost universally sacrifice customer safety for profit. Especially when they are making a decision between "for sure losing opportunity money" and "maybe losing money after a court case".
That does not mean they aren't liable when things go bad.
Nacchio simply tried to use it as an excuse. He was just throwing shit against the wall and hoping that some of it stuck. Here's his claim: he was not in a rightful state of mind when he sold his shares because of problems with his son, and the imminent announcement of a number of government contracts.
Yeah sure, I know exactly what he means. Whenever I'm not in a "rightful state of mind" the way I cope with it is to dump company stock that I'm restricted from selling. /s
Nacchio was nothing but a greedy scumbag, and he went to Federal prison because of it.