The policy is happening at the lemmy.world level, not the individual mod level.
It's right there in the Terms of Service (which nobody actually ever reads):
https://legal.lemmy.world/tos/
"1. Attacks on users or groups
Before using the website, remember you will be interacting with actual, real people and communities. Lemmy.World is not a place for you to attack other people or groups of people. Just because you disagree with someone doesn't give you the right to harass them. Discuss ideas and be critical of principles. Show the respect you desire to receive.
We do not tolerate threats of and calls for violence in any form against any living creature."
We faced the same problem in the Politics community when Henry Kissinger died.