+1 against defederation
If in fact they are the owner of all these accounts and are genuinely trolling this post accomplishes little more than giving them the attention they crave. What's to stop them from just making more new accounts and continuing to farm attention?
If they aren't trolling and do not own these alts then we are just banning someone that some people find annoying.
This proposal clearly well intentioned, but I personally feel that this is a double edged sword. The people most bothered by this individual have likely already blocked them personally. If you ban them on an instance level and they make new accounts you may unintentionally re-expose those users to this person they already saw fit to block.
