Besides Palomar Mountain State Park (which is not where the guy was flying from), there are numerous desert state parks that also do not allow drones to be flown from within them, including Anza Borrego, Salton Sea, etc.
The only time you're not allowed to fly from National Forest Lands is when they are "Designated Wilderness Areas". There are also times when TFRs are in place, or an area may be close due to nesting seasons.
Other than that, it's legal. Just...
I disagree, education is an important part of how we deal with the general public and with customers- especially if one wants to have a continuing business relationship with them.