Restrictions are not the same thing as obligations. Copyleft licenses are not more "restrictive" than permissive licenses, but they do have more obligations. Permissive licenses have obligations, too, such as the inclusion of a copyright notice.
Copyleft is not "restrictive"; it does not discriminate against any field of use, and if it did it would not qualify as free software nor as open source.
Permissive licenses posit that freedom comes from having relatively few obligations; copyleft posits that freedom is a guarantee of rights.
Neither approach is "restrictive", and the latter is more free by any reasonable definition of freedom.