Maybe where I went wrong is that, even knowing you weren't using a more common meaning of monster, I still made some assumptions based on it, namely: monsters are (or seem) inhuman, irredeemable, undeserving of sympathy, and best removed from society. I also assumed that what made Nathan and Amanda monsters to you is their respective exploitation of others, aka "profiting off of bad behavior."

But, monster is a superlative: there isn't much worse you can be. If you are calling a plurality or majority of people 'the worst kind of human,' does the term not lose utility? Do you use it as a mere stand-in for 'bad person?'

That is why I asked: Is the person who stole someone else's lunch from the fridge at work (an unfathomable act, to me) a monster in the same way that any person in federal prison is?

This may seem less serious than I intend it to be. I do think stealing a colleague's lunch is a sign of severely compromised morality, but I wouldn't default to calling them a monster.

This ultimately matters to me, because I am concerned about the outcome. If we characterize people who do bad things as monsters or 'bad people,' it may follow that they be denied any sympathy, humane treatment in prisons or a path to rehabilitation. None of this is to diminish the harm to victims, whose concerns are a priority. As such, I would posit this is a significant reason that sexual assault in men's prisons is tolerated or accepted as serving justice. The larger and more absolute the category, the more people are subject to that outcome.

I also tend to be a bit hypervigilant about anticipated objections. This may appear as a lack of clarity of opinion when it is intended to be concession for the sake of discussion.