User blog comment:Kirkburn/Technical Update: July 25, 2016/@comment-24014422-20160728191617/@comment-126761-20160729151842

Regarding the idea of making user pages editable only by those users (and admins) - it is something we've discussed before, but the benefits have never really felt like they strongly outweigh the disadvantages.

We certainly do think users should feel reasonable 'ownership' over their user pages - but in general we want to try to avoid locking things down too much. For example, users sometimes include text that others will want to update on their pages - e.g. links to renamed pages, links to templates that no longer exist, etc.