This isn't about one downvote. After 5 years I never reached the 501 karma required just to downvote, a basic function. That's a system that rewards conformity while suppressing dissent.
When I updated this bio with critique, the moderator asked if I wanted my account closed. When I pressed for an explanation, and pointed out how downvotes coincided with my emails, I got silence. That silence is its own answer.
HN isn't an open forum. It's internet feudalism: users generate the content, the lords guard the system, and feedback about that arrangement is unwelcome. That's why I'm done.