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.
My hope for the Fediverse is, sure. We can just allow people to be sad little kings of their sad little hills. If it’s enough of a problem, everyone else can go to some other community, possibly on some other instance.