“Such men certainly existed”
Yes they, and they were called the Knights Templar.
I'm not trying to say men of the Middle Ages were better than those of today. Human nature is eternal.
But in a society based on honor and vows, those who were perceived to be dishonorable paid a very steep price indeed.
What bothered me about GOT was the open disdain of characters for honor. A very unusual attitude indeed for the Middle Ages, where even the most dishonorable actors attempted to portray themselves as honorable.
And none of the wildly and openly dishonorable behavior in GOT seems to phase their followers, who are themselves dependent on their lords' honor.
Reminded me of one of the Batman movies, where the Joker is constantly murdering his minions, yet always seems to have a fresh crop of loyal henchmen on hand whenever he needs them. That just doesn't work.