I don’t know tbh. You can make two copies of essentially the same community around the same interests/subjects with different names, underscore or no underscore. I think “mechanically” solving a problem like that is not a great idea, and that defining if two community should be merge fall into the hands of admins and administrators, not developers. If you are a mod of a community, or admin of an instance, chances are you know that such “clones” exist, and you either think you should merge and do it, or think you have a valid reason to stay apart and are free to do so.
I guess there is a difference between accepting discussions around a subject with people you disagree with, and accepting someone creating an account specifically designed and named with only one goal : bad faith and low effort posts (yes this is what such a username clearly seems to announce to me).
I spend much time having great discussions with people both online and afk about vaccines, people who are both pro or anti, and it is sincerely interesting. But seeing such a username is as stupid as seeing someone named “vaccineguaranteeyoursurvival”. Those username are themselves clearly false statement that are meant to create unusefull discussions.
Hope this ban isn’t getting canceled.