Plus the format itself. Twitter is inherently optimised for soundbites. Nuance and high-impact, 5-seconds-at-a-time communication don't really mix.
Then add the incentives built into any (anti)social network: they automate piling on. Engagement über alles, users be damned.
[I am painfully aware of the irony of posting a critical post about Twitter, quoting material that was originally posted at Twitter. The notion of pileon automation comes off of this tweet: https://twitter.com/mcclure111/status/1143950836533473286?la...]
The medium is the message and sooner or later the twitter mechanisms get everyone regardless whether you have good social media hygiene. It's built for outrage. Instantanious nature, slot-machine like feeds, blinking like buttons, 'getting ratio'd', virality, this is what it's built for.