New wave of janitors are incoming.

How do you ensure that free speech and shitposting on 4chan is protected (/b/ e.g.)
How do you ensure that discord trannies or other biased idiots are not trying to infiltrate 4chan?
How do you ensure that janitors are not causing any damage by silencing people (deleting perfectly good posts/threads)

Is there any safety measures against that? Do you check janitors for their work?