As Pierce notes, it's rather laughable for a pundit universe which includes Ann Coulter to question whether Bruce Springsteen should just STFU because he's merely a musician.
But, more generally, there's no qualification or particular expertise or license one obtains to get to talk about politics on stage, on cable, on the radio, or on the internets. In outlets with barriers like TV and radio, some people magically enter the "pundit club" through various channels. Some people earn their key to face time by being on enough rolodexes. Some people are actually experts in some stuff. But, for a long time punditry has consisted of people who don't necessarily know what the hell they're talking about posing as experts in just about everything. That's not necessarily as bad as it sounds, but it's made better if we strip away the pretense that everyone invited to talk about stuff on the TeeVee is actually an expert.