The mod banning these users is the same mod who made the posts they downvoted. This is mod abuse, turning the downvote button into an auto-self-ban button.
The message is “If you disagree with me, you will be banned”
Monitoring and banning users for using lemmy as intended to signal boost your opinion should be grounds to have all mod privileges removed. This behaviour undermines the integrity of the server and the wider fediverse.
But these clowns are surprisingly common and much more of a problem than some trigger happy votes.
Then power-hungry moderators who behave like this can sully their reputation, risk the ire of the instance admin who may remove them over this, and if not - also risk the ire of the fediverse who might just recreate their community on another instance and supplant them.
And it’s a lot easier to notice and act on bad behavior when activity is public. Maybe on a centralized service that can afford full time moderation staff, you could restrict that information more effectively, but considering the fediverse is community driven, I think this is an effective choice
You’re probably right about that.