The license-writer's published opinion on whether an activity is a copyright-protected activity that needs a license is of no special status (if the license-writer is also the copyright holder, it might have special status as itself being an implicit license in those circumstances where the opinion is that a license is not necessary.)

What is controlling on this question is copyright law, not the FSF's opinion. And, clearly, the FSF isn't a neutral authority here, they have a positive interest in portraying the need for a license as being as broadly as they can to encourage use of the license and adherence to its other conditions.