I think I might have caused a misunderstanding of the issue (I was trying to be brief). It really doesn't matter who I'm running compass as (root or otherwise), the issue is that the container is writing files to my host with a different UID:GID then the one I'm using on my host machine.
I wouldn't normally run compass as root, it was incidental to the actual issue.
Don't run anything as root unnecessarily.
(Your problem is likely because you refer to the root namespace as a "host". It is common practice, but leads people to bad conclusions.)