I think there's a virtuous spiral when the one (specific platform features, philosophy, and conventions) reinforces the other (people's perceptions, attitudes, and interactions), and people care about excellence.
The for-profit, outrage-seeking, clickbait model of "engagement" is the opposite of that.
We can't fix everything with technology (if there's still people problems) or with good people (if the platform fails them) alone.
We need platforms that encourage the good stuff and minimize or discourage the bad. Not the other way around.