Thanks for demonstrating your lack of credibility.
Uninstallers by and large only do the reverse of what an installer did by going through the install log and undoing what it did.
This means any additional files made after the the installation that weren't properly appended to the log, any additional information added to the Registry that weren't properly appended to the log, and any user files created after installation (eg: save files) will not be touched by the uninstaller.
Should everything be properly logged for clean uninstalling? Yes; Linux package managers are a decent example. But reality is not ideal, so we have to deal with practicality. This presumably is the case whether it's Windows, Mac, or Linux.
The user-specific parts of the registry are powered by files in the user‘s profile and ACLs do not normally allow other users to have access, so the same issue applies there too
lots of them leave crud in HKLM/System and HKLM/Software, as well as I think HKey_Curent_Config
I dont mind the per user settings crud, I do mind the system wide crud, because it can make reinstating the app to resolve an issue fraught, and I have to go manually find whatever opaque keys were set and remove them.
Thanks for demonstrating your lack of credibility.
Uninstallers by and large only do the reverse of what an installer did by going through the install log and undoing what it did.
This means any additional files made after the the installation that weren't properly appended to the log, any additional information added to the Registry that weren't properly appended to the log, and any user files created after installation (eg: save files) will not be touched by the uninstaller.
Should everything be properly logged for clean uninstalling? Yes; Linux package managers are a decent example. But reality is not ideal, so we have to deal with practicality. This presumably is the case whether it's Windows, Mac, or Linux.