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.
This does not work at all. There are many threads being participated in all the time on all kinds of communities. If we did it this way, we would get a new set of posts on the front page every time you refresh, simply because 20 comments had been posted in 20 threads that just happen to be the newest comments. This model of last bump only works if activity is fairly low.
It works on 4chan which has much higher traffic.