My operating system is Linux Mint: The Seafile directory keeps coming back again and again, even after I permanently uninstall everything. I have never seen that before. How do I permanently remove this crap? I am not interested in Seafile.
I assume you mean the seafile directory in your home directory is what keeps coming back, right?
You say you uninstalled seafile programs from your computer, but the most likely reason I can think of for that directory to be recreated is if you missed a program that is recreating that directory when it starts. You can search through programs running on your machine with this command ps aux | grep seafile to see if it is running. If it is, the path to the program it reports could help us figure out what steps you need to do to remove that remaining piece.
It would also be worth looking in your ~/.config/autostart/ directory for anything seafile related. That’s the most common way that the program would be configured to run automatically when you log in.