And, it is not enough to just enable the root user.
You have to log in to that root account.
(And I agree - you also need to have SIP disabled for certain kinds of files, which would include those found at the root of the volume)
Just try to avoid this specific command (sudo rm -rf) from the command line if possible.
It is a very powerful command and if you do a mistake it is irreversible.
Read about what it can do. Terminal > man rm
In my opinion it is better to enable the "root' user, do the job and disable it if you are new user.
It is an alternative better than running root commands using Terminal. Especially if there is no backup.
Just think about it!
My suggestion would be once SIP is disabled and the OS Volume is mounted RW, enable root user, login as root user and drag the folder to the trash and empty the trash. Safer than using rm -rf from the Terminal.