If the photographer is asking others to stay out of his area when he is shooting models or anything else in a public area then it would be reasonable to require a permit.
If a photographer does not bother anyone who decides to set up chairs, barbecue, throw a frisbee, take a swim, or use the area in a appropriate manner for the intended land use then I guess the Park Ranger or anyone else would not have a grip.
I think we have all come across a few commercial photographers who are taking photographs of a wedding party, family portraits, corporate work, etc., in public spaces. Most people don't seem to mind but I guess somebody along the way pushed the envelope and caused complaints. Then there is always the local, state, and federal government looking to raise revenues through fees for use. The state of Washington charges residents $30.00 a year to use State Parks and there are probably rules regarding photography and video permits.
Bottom line if you are interfering with the general public using public property then a permit would appear to be reasonable.
I'll leave the pricing to the professional legislators since I am sure it is a well thought out policy. 😉