I'm not sure how people arrive on the platform expecting Upwork to be some sort of magical idiot-free oasis.
How would I handle the situation? Exactly the way you did, except I've developed a thicker skin, and after the initial shock and irritation at having my time wasted, I wouldn't be tempted to waste more of it analyzing how someone I don't know and will likely never encounter again could have the audacity to pass moral judgments on me. My time and energy are too important to waste.
A word of advice: if you describe this brief negative encounter as "frustrating me beyond what I expected," freelancing may not be for you. There's an endless supply of similar idiots in different packages, and Upwork gives you access to them on a global scale! If you spend this much time analyzing every insult from every random idiot you encounter from every possible angle, you'll die of exhaustion.
You did well to avoid this client. Stop analyzing the insult and put your energy into finding one you want to work with. There are a lot of good ones out there. That's why we're here.
re: "I'm not sure how people arrive on the platform expecting Upwork to be some sort of magical idiot-free oasis."
Perhaps they read the Community Forum first and assume the platform as a whole is just as heavenly.
In freelancing and business in general its always a good skill to learn how to grow a thick skin.
Thankfully I worked at a fast food restaurant for many years as a cashier and assistant manager, and I definately have learned how to brush these kinds of things off to the side.
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