Long time user of Elance and then Upwork here. I can attest, what occurred in this story is common.
The problem that Upwork doesn't realize is that without an active and happy freelancing demographic, clients will go elsewhere. Historically, Upwork has made it a priority of catering to the client. This is evident given their JSS. For those of you who are not familiar with JSS, it is a score that companies / clients use to hire freelancers. Now, one would assume the score is based on past work with clients. This is not all the score accounts for. Timeliness is responding to invites, the number of long-term clients you maintain, the number of clients you hassle (yes, Upwork actively goes out and tells it's freelancers to hassle their clients to leave them feedback - the responsibility falls on the freelancer and only the freelancer), etc.
Thus, when clients don't leave feedback (for whatever reason), you are dinged. Upwork won't tell you by how much exactly so let me give you an example.
12 months ago, my score was 92% (Top Rated). A client hired me. We went over the terms of the contract (# of revisions, not working on the weekends, etc.). 2 weeks into the project, the client started to deviate from the terms of the contract. I let them know and they began to get pissy. This happens all the time as Upwork has created a platform where the clients hold all of the power, and they know this.
A week later the contract wrapped up, and I managed to make the client happy as they left me a 4.7/5 on my profile and a positive review. Clients are able to leave private feedback the freelancer can never see. When the JSS score updated (every two weeks I believe-mind you, I had not worked any other jobs since that job) my score went from 92% to 71%! A 21% drop.
Suffice to say, for the past 12 months, dozens and dozens of clients later (most with positive reviews); I am now only sitting in the low 80's for my JSS.
In conclusion, Upwork is the worst example of an online marketplace for freelancers who have a backbone and are not afraid to tell a client how it is. After all, we are hired for our expertise and when a client proceeds to tell us how to do our job, it poisons the freelancing community.
edit: spelling errors.