User blog comment:Kirkburn/Technical Update: September 2, 2015/@comment-3388044-20150904013930/@comment-126761-20150904174829

Yes, this is intentional for the moment - again, as mentioned, we want to take careful steps forward around these issues. We have no particular desire to stop users editing JS that runs only on their own account - but many communities import scripts from the user namespace. This is not ideal, and we want to approach that problem sensibly, in a way that does not cause more problems than it solves.

This is not a simple area to solve - but we're working hard on it.