You pretend there is some objective and reasonable definition of “propriety and civil discourse.” There is not. If someone posts to Twitter the Biblical view of “transgenderism” on “International Day of Transgender Awareness” then they are subject to suspension.
I'm not pretending anything. You've lost track of the thread of this conversation. What was being discussed was how a topic was being discussed, not that certain topics were off limits or get shut down. No topic of discussion should be off the table, but the discussion itself should be conducted with propriety and civilly.