I'm using Win8, where the rights management is very obscure :-(
But that's not the problem, provided that the library manager wants to protect the installed libraries. Based on my experiences I'd suggest that the library manager allows to uninstall libraries as well, at least conversion of original (protected, immutable) libraries into mutable ones.
Renaming libraries is not always a good idea, as long as this means that the file names have to be changed, and consequently all #includes, in a project or in multiple projects, have to be modified. This may be okay for the average user, but not when a developer can use a versioning system (git...) to switch among versions of the same library.