Personally, ignore is a great feature, as is hush. But mute is straight-out censorship, and is both ineffective and prone to abuse.

(Ineffective because someone can always create a throwaway account, prone to abuse because someone can censor any response to their post)

To put it simply: I personally believe it's fine for person B to refuse to allow person A to talk to them, but not for person C to refuse to allow person A to talk to person B.