Another reason to block an instance is language. For example, https://feddit.de is a non-English language instance, I’ll never interact with anything from there.

Though, perhaps that’s a separate issue. Maybe users should be able to set their language(s) and content can be blocked if it’s not in your language(s).

Probably best to do it hierarchically, where instances have a default language, magazines can override the default instance language, and posts can overwrite the default magazine language.