AMD Information Center and Documentation Navigator are not removed during uninstallation. Both are intended to be standalone applications common to multiple versions of AMD tools.
If the applications are no longer required, they must be uninstalled separately through the corresponding entry in the Start Menu program group, or for Windows, use the Uninstall or change a program control panel option.
In Linux, Uninstalling the AMD Vivado™ Design Suite tool does not need any root privileges if you have access to that path and there are not any instances of the tool open from that installation.
In Windows, you will require Administrator privilege if you plan to uninstall using the command line options. Uninstalling using XIC does not require any admin privilege.