Sean Penn believes that COVID-19 vaccinations should be mandatory for all, just like “turning your headlights on in the car at night.” Penn — who made headlines last month after refusing to return to work until everybody on “Gaslit,” a Starz series he co-stars with Julia Roberts, got vaccinated against COVID-19 — is doubling down on his stance. Speaking with CNN’s Michael Smerconish on Saturday morning about his new film “Flag Day,” the two-time Oscar-winning actor said that he is “so grateful” that audiences will have an opportunity to see the movie in the theaters. “It’s rare these days to h...