Because people want to play games and https://xkcd.com/1200/
Most platforms are edging towards sandboxing applications, with OS X app store, UWP, and the various Linux snap/flatpak/appimage etc things. Web apps and iOS/Android have their own tings.
The only plausible attack scenario is if you steal my computer while I'm logged into my KeePassX. It has all my passwords visible. But that session times out as well.
Riot installing a kernel module is more like the latter.
Just request a password reset and change it to whatever you'd like.