https://support.mozilla.org/ko/kb/how-disable-enterprise-roo...

Apparently this was done to please annoying AV softwares [1].

[1] https://static.googleusercontent.com/media/research.google.c...

This isn't the right summary. Firefox uses it own root store still and ignores any certificates distributed by default in the OS. However, if the user installs their root to the OS, Firefox will also pick it up. This is how other browsers work.