I have a baseline level of caring for everyone, even the people I will make every effort to keep far far away from me and from anyone and anything I care about.
I stayed there that long because I had a really thick skin and the benefits of staying far outweighed leaving. I rationalised that he could sack me tomorrow, but every day I got more experience and satisfied clients. In the end he was the cause of too many other people leaving, seeding so many mortal enemies into the industry at quite high levels, he tried to blame me for 'white anting' him, but finally sacked me, that backfired spectacularly and the company folded soon after.
I managed to pick up a great job off the back of what I'd done at that company so it worked out really well.
I dealt with it with a thick skin. I did feel empathy towards someone who must have been treated very badly some time in their early life, could not bring themselves to trust their staff and felt compelled to lie even when the truth would have been OK. What a terrible burden to carry for someone who was quite well off.
In hindsight I should have left, but personal circumstances at the time limited that option.
On the internet: Of course not. It's impossible.
IRL: Mostly not, with few exceptions.
I've recently realised I've had 4 people in my life who would definitely fall under varying combinations of sociopath and narcissist and looking back with hindsight they've not changed in any positive way whatsoever and most other people we both knew have moved away from them - https://www.vice.com/en/article/evg45k/narcissists-will-even....
The best way to deal with these people is to slowly move out of their lives - find out what they have no interest in and visibly show interest in it as something that occupies your time.
There's plenty of less exciting, less drama filled but more deserving people in life to give empathy and your time to.