Even worse are Unix utilities that leave dotfiles in every single directory they touch. Just because they're hidden doesn't mean that they're not dirty! Pleas keep your crap restricted to ~/.config, which exists for this very reason.
On GNU/Linux systems maybe, it isn't part of POSIX.
How will you enforce something like that to all UNIX eco-system?
Otherwise you get inconsistent behavior such as metadata being synced when you copy entire folders, but not when you copy individual files. Then you have to rely on even more hacks to get around that, like detecting when a file is copied and automatically copying the corresponding dotfile. Sooner or later you end up with a complete mess.
1) This is not default behaviour, you have to specifically enable this
2) They actually note that if you copy files outside their app, metadata does not get copied, it's doubtful they'll fix it
So basically, NOFIX, working as intended. Not poor design.