I have the same issue. I want to use my OWN folders, of my own choosing (name) and not some "silly", generic ones, imposed by the system.
Now I hide them using the "Hide from public" checkbox but they need to be removed.
Where have you seen this option, for those 3 default folders? Hiding them would be enough for me. I just don't want them showing up. They can stay there, if the package developer "needs" them (probably to sleep better at night?), as long as they're empty!
I really can't imagine a valid reason to have those 3 folders, since the app works perfectly well, with them empty. Also, if you take into account all the cultures/languages, where a synology is/can be used, it absolutely makes no sense to impose folder names!
Makes me wonder if this app is really from Synology (creators of the best NAS) or some third party...
Hope you guys fix this soon!