Which is pretty much like saying, "I knew if I lay with a dog, I would get up with fleas -- but the dog told me to and I couldn't say no."
That's actually an explanation I can understand. In the late 1950s, a psychologist designed an experiment to determine whether Germans possessed peculiar character traits that made them susceptible to falling under Nazi sway. Before taking his experiment to Germany, he did couple of test runs in his own college town. Those tests became one of the most famous psychological experiments in the literature. Stanley Milgram showed that even normal residents of New Haven, Connecticut, would inflict painful and even dangerous electrical shocks on innocent strangers when ordered to do so by persons they believed to be in authority. After that revelation, Milgram saw no point taking his experiment to Germany. https://www.mtholyoke.edu/~apkokot/basisexp.htm.
More recent research in behavioral economics suggests that this blind obedience is due to our fundamental laziness. We will always take the path of least resistance, that which requires the least mental effort. It is easier, it will always be easier, to do as you're told, to just follow orders, than to do the hard work of rethinking your assumptions, beliefs and commitments, and then to say "no" to an authority figure.
That is why I have such empathy for the many clients I've represented over the years, in DOJ, SEC and FINRA investigations and prosecutions, whose essential explanation was that despite their misgivings, they were only doing what they understood their bosses or their firm or the market expected of them. There were brokers who thought "truthful hyperbole" was, well, honest, because everyone did it. There were traders who just followed firm-sanctioned trading desk procedures as they went about skimming a basis point here and a basis point there for the greater profit of the firm. There were salesmen who persuasively sold financial products they didn't themselves believe in, because that's what they were trained to do and what their firm told them to do. They were, all of them, little Michael Cohens blindly loyal to a boss, a firm, a peer group, an accepted practice, or -- the most self-aware of them all -- a fast buck.
I'm not saying that "I was just following orders" is a good excuse. It wasn't at Nuremburg and it isn't here and now, as Flynn, Cohen and many others will learn. I'm only saying that the inclination to follow orders is a well-known human frailty. Therefore, those who exploit that frailty by giving orders are doubly responsible for the consequences. He who gave the orders is ultimately the most responsible for Flynn's and Cohen's lies, and also for letting sick little girls die in federal custody (https://wapo.st/2QyC4ai) and for stranding desperate refugees in Mexico to have 6-digit numbers written on their forearms (https://bit.ly/2UO69RC). The ill consequences of bad orders are hard to stomach, and it's good they are.
In Game of Thrones, there is a form of knight's oath that, so far as I can tell, is original. At least, I have not found anything like it in historical feudal practice. The Thrones knight pledges loyalty and service. In return, the lord pledges room, board, and this: "to ask no service of you that might bring you dishonor." The fictional lord promises never to give an order that shouldn't be followed, and that's really quite remarkable. Imagine all the modern analogues of feudal lords -- all the corporations, department and desk heads, bosses and political leaders -- pledging never to give an order that might dishonor an underling. Or would that be taking fantasy too far?