I think that's the main reason I'm reluctant to run curl|bash-ware. I might trust the authors not to be malicious, but I generally wouldn't trust them to be competent at cleaning up after themselves.
However, having a package that simply installs some files and then tells you "copy these lines to your .bashrc and modify this mount file and [...]" to set up your system is really not that much better - if you follow those instructions, it will be up to you to manually un-follow them if you later decide to stop using this package. And while whoever wrote the installer may or may not properly undo what what they installed in the uninstaller, I can guarantee that no one will provide an uninstaller which un-does changes you manually made.
cc: Anyone working on macOS
There are certainly other ways to do that, but this is how it has been done since forever.
In my experience what is common will be the inverse of that. And leaving config files spread throughout the system is one thing. Sometimes the uninstaller doesn't even remove the Program Files directory leaving it behind with cache, tmp files, etc. (Things that shouldn't even be there in first place but anyway.)
The config and data is iffy situation because you might want to uninstall just to install new version, and so might want them to stay, might want them gone.
It's possible for installers to be this full-featured, but it's plagued with footguns.
They try and often fail to make an idempotent shellrc patcher with command line pipes, or something equally convoluted. If at all.
Instead of using something established, or even better... drop-in config directories.
Not everything needs to own (or even touch) the main config file!
edit: Don't trust the 'curl the script before piping it' thing, either.
I don't have it handy, but there's been demonstrated means to alter the content based on timing, causing the pipe to be a malicious payload
Even workse if app starts with sudo to install some stuff in system directories