Earlier quoted context omitted.
If knowledge is to be free, that means there should be no restrictions on how it is used. Even an open source license misses the point, because the implication is still that one person can dictate how another person can make use of knowledge. It’s still premised on the same dystopian view that a person can own an idea.
Not so. Stallman created copyleft licenses as a defense against the current implementation of copyright. Copyleft uses the existing system of copyright to protect authors of free software from people who want to use copyright to restrict distribution. It wouldn't be necessary if copyright didn't exist.
Copyleft was created to protect users of free software from authors/distributors who tried to use copyright to control the software running on the users' computers.