It's worse than that, if you read more comments, they're actively breaking Firefox (reader mode, etc). It's not the IE era of benign neglect.

Some of the comments are helpful in building in a better business case, such as this one: https://www.reddit.com/r/webdev/comments/8hha0r/is_it_worth_... . In summary /u/wedragon says that users have multiple environments and even multiple browsers. Damaging or disabling Firefox on the desktop may lose the profitable mobile side where the user may have Safari or Chrome.