You touch upon an important point.
I think one of the most preposterous ommissions manifest on the Upwork platform is that the number of refund requests and disputes a client has filed is not prominently displayed as a part of every client's stats.
It would totally make sense if every freelancer could see that, as part of a job posting:
"This client wants me to write an article for his website? What's this? This client has had 10 refunds issued to her? Well... maybe she's just getting the work done and then using it without paying for it. I think I'll pass."
There IS NOTHING WRONG with a client who hires a freelancer... and then the freelancer has a family issue come up and can't do the task, and issues a refund. But when a client REQUESTS a refund... That should be information availble to freelancers to help them make an informed decision.
I have read the Community Forum extensively, and I can say with certainty that the vast majority of refund requests mentioned in the Forum are inappropriate and represent unethical, unprofessional and immoral behavior on the part of the client.
you are describing a truly horrible client.
But the overwhelming majority of clients on Upwork are fantastic people, professional, and honorable.
The truth is, Upwork freelancers rarely come to the Forum to complain about great clients with whom they had a great experience. So what we mainly read about are the problem situations, which are the exception, not the norm.
If you won't want to continue using Upwork as a freelancer, that is fine. But it would be inaccurate to think that this specific client is representative of the platform's clients as a whole.