> HN has all sorts of sneaky punishments to keep people from noticing what's going on

Another way of putting this is that HN has very standard mechanisms in place to combat spam and other sources of low-signal comments.

> Shadow bans, limiting how many comments you can post per day

Like these.

> Sometimes outright refusing to serve you pages with a "Sorry." error,

This just sounds like downtime/server problems. Every site has them, and even the most law-abiding posters on HN will see that sometimes.

> even flagging isn't visible to the person whose comment got flagged.

Yes it is?

> HN doesn't notify you in any way for any of this.

This is by design; HN doesn't offer notifications of anything on its own. Besides, most platforms don't usually notify people of these things by default either?

> Even this account is shadowbanned - and this comment automatically flagged - because I had the audacity to create an account with a VPN, in a world where VPNs are a requirement for unrestricted Internet access for a growing number of people living in "democratic" countries. The only way I know this is through testing, of course, because HN gives no indication that your account will be shadowbanned on creation.

I don't think you need to be so indignant. VPNs are also abused. All of these mechanisms are tradeoffs for making HN one of the best sites I've ever been on for productive, intelligent discussion; and the mods are well aware of this and manage to balance it well. For example, you were still able to register, and you and I are still able to exchange comments. If you contribute to discussions (on an account you don't just throwaway) for a little while, the limitations go away.