but then it needs to come with a curl|bash uninstall tool. Most of these install scripts are just half the story, and the uninstalling part doesn't exist.
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.