Such a massive opinion against Upwork makes me also worry. It almost sounds like i have to build other ways of reaching my customers as if too many people feel like this, Upwork may go under.

Sorry you feel so bad guys. I made over a million bucks on Upwork and my customers are happy, many work with me over years, and the only time i got in serious trouble was actually the only time when i tried to trick my customer myself, so i was entirely at fault.