the point of the post is that there's also a danger in withdrawing from participating in the public and that there's a significant downside to the public and oneself when we withdraw from discourse, so I don't think there's a contradiction here at all.

You can criticize a system and still participate in it. The author also stated that they only posted on Medium after vetting their ideas with a more private group.

I've posted criticisms of FB on FB. What else are you gonna do when there really is no choice. this kind of criticisms really are ad-homenian attacks with little to contribute.