Dick Metalf was once a successful commentator in the media on the subject of guns. Now he's out. He stepped out of the box into the terrain of controversy about guns. Here is coverage on that by THE NEW YORK TIMES.
Often it's binary: You communicate what does not violate expectations of those who pay your salary, directly or indirectly. Or you decide that it is your right to speak your mind and perhaps your conscience.
There are many subjects on which public figures like Metcalf can speak their minds, without threatening how they make a living. We all do that, all the time. Only the reckless or a newbie who does not understand the rules breaks them.
Yes, it's a bit like the rule in the Garden of Paradise. You could eat anything you want but the fruit of one tree.