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.
I downvoted your comments because I’m petty and it’s fun and it doesn’t matter very much. We started out all high minded and now we’re here, in the mud, slinging mud, like the Jacobins. So you win. Here’s a box of wheat starch for your 'do, live it up.