Thing is, human psychology is extremely complex. We've barely scratched the surface of how our brains work, and society is moving so fast now that analysing the impact of all facets of modern life in real time is almost impossible.
I would argue that people who continuous do harm that impacts themselves and other people are mentally unwell / unstable.
When someone does harm to you or your loved ones, in the vast majority of cases, despite the profound distress and hurt you experience as a victim, you generally don't retaliate in kind because ultimately you give a shit about the long term consequences. People who continually behave in a shitty manner are lacking the capacity in some way to exercise self control. Maybe it's "faulty wiring" or chemical imbalance or an unknown brain injury. It doesn't excuse what they've done, but it could be a reason.
Psychosis, psychopathy, sociopathy are all diagnoses applied to people who behave outside of what society deems as "normal".
The examples in the OP could fall into any of these categories.
I don't deny that some people will never respond to treatment or rehabilitation so for the good of society and to prevent ongoing harm, they need to face consequences such as deprivation of liberty.
I also believe that people need better support to safeguard their mental well-being from as early an age as possible.
The backgrounds of some heinous criminals can be analysed and certain things crop up again and again, alot of which is influenced by environment and generational cycles.
The complaints that "normal" emotions are pathologized and leveraged inappropriately as excuses for poor behaviour in more mundane settings is somewhat valid, however, this has coincided with the explosion of the Internet and social media, something else that needs to be explored. There is a constant feed that if you just do this that or the other, you'll be happy and successful, then the message that if it's not working for you, you're just not trying hard enough, and from there, there must be something fundamentally wrong with you. It ignores all the external influences that might explain why you can't just magic up a perfect life by being "resilient" and "determined".
Then we have the whole emphasis on personal responsibility and aforementioned resilience, and the withdrawal from real world community, atomisation if family etc etc, and all of this can breed insecurity and cimognitive dissonance.
It's a fascinating and complex subject, and some are interested in it, others scoff at "excessive naval gazing" - such idms the paradoxical nature of modern life.
One thing that I do see though, is that society is often only a whisker away from mob and pitchfork mentality, which is worrying. Marginalising and stereotyping people breeds suspicion and resentment, and thus we have self-fulfilling prophecies in the making.
I'll take a period of excessive navel gazing followed by a more informed middle ground over the alternative any day. After all, there is no cast iron guarantee that any one of us may succumb to serious mental illness for a myriad if reasons. And when it's you, I guarantee that you'll appreciate any crumb of understanding or mitigation in your defence.