Problem to solve
User pages are collaborative spaces often used for creating to-do lists, collections of helpful links or tools, and snippets of copy-and-paste wikitext. Many userpages are also curated by the associated user account to share autobiographical information, either in an encyclopedic format or in a more personal and social format. This information, coupled with the fact that the page is associated with their username, is a part of the user's identity.
Vandalism to user pages are not standard content vandalism, they are a form of personal attacks designed to hurt or humiliate the subject of the userpage. Patrolling the AbuseFilter logs shows some horrendous personal attacks to illustrate the types of hurtful messages.
After a lengthy conversation on ENWP and a vote on FRWP, an AbuseFilter (#803 on ENWP) was enabled that prohibits IPs and newly registered accounts from editing the base user pages of all other accounts by default, individual users can override this with a special template if they wish. User talk pages were not touched. In the discussion stronger protection limits were proposed, but ultimately rejected due to the scale of the solution.
However, sometimes unwanted edits can come from a user who is above the autoconfirmed threshold. Admins can impose interaction bans or manually protect the page on behalf of the user, but this requires a public conversation.
Provide users with a tool that allows them to prohibit specific usernames from editing their userpage and subpages. This could take the model of the Notifications Mute or Direct Email Mute features, or manifest as something different entirely, such as an admin-controlled per-page blocking feature.