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.
From your link:
This is a noble intention and not without merit. However it completely falls apart when it’s YOUR posts that you’re banning people for downvoting.
For many niche communities, the moderator is very often the sole poster as well. While I can see the perceived conflict of interest, kickstarting niche communities is challenging.
So challenging that you need to protect your own feelings by banning anyone who downvotes you, so that you don’t decide to leave a community that you’re already in a position of power over? Grow a pair.
What “power” does the mod have if the community doesn’t have other members?