Can't un-exclude directories with `dropbox.py exclude remove <directory>` on Ubuntu 20.04.2

I can confirm, the exclude is useless at this point, the behavior is so random and this is so frustrating. When you add a folder to the exclude list, what dropbox seems to do, is to download that folder fully, and then delete it, and eventually, that folder's name will disappear from the exclude list out of no reason, even though it indeed is not being synced, and you can no longer sync that folder ever again without reinstalling the whole thing. Who invented this mechanism? He/she single-handedly wasted all these resources of network and time of ours.