I respectfully disagree. If everyone just posted everything was fine when its not, thats really just propaganda. Imagine if that happened on the Titanic.... oh wait. Anyway, I agree Steemit is the best site out there, but it could do a lot better.
I would counter that people posting about negative aspects of Steemit are really raising awareness of its imperfections for others to reflect on. It does not mean they have a permanent negative mindset like a depressed person in need of counselling.
I guess the sad feeling is seeing something you love degenerate into something akin to the real world where the ideal was to help everyone be their best, but is spiraling into haves and have nots again.
I must say, I am a glass-half-full person so I know what you are saying. But there are positives to be found in complaining sometimes as well.
Have a great day! :-)