Sadly, a great many 3rd party developers don't give a single shit about uninstallation, and won't lift a finger to do it cleanly, correctly and completely. If their installer/packager happens to do it, great, but they're not going to spend development cycles making it wonderful.

This is why its so upsetting over in Linux land how so many people are just itching to move away from distro package managers and package maintainers. Curl | bash is everywhere now because "packaging is hard" and devs can't be arsed to actually package their software for the OS they developed it for.

Like, yeah I get it - it's frustrating when xyz software you want isn't in the repos, but (assuming it's open source) you're also welcome to package it up for your distro yourself. We already learned lessons from Windows where installers and "uninstallers" don't respect you or your filesystem. Package managers solved this problem many, many years ago.