When Meryl Streep criticized President-Elect Trump and appealed to common decency — and when the cast of “Hamilton” did the same — Trump’s die-hard supporters were livid. “Stick to acting,” they shouted. “We don’t want to hear your political opinions.” But to deny such statements is to deny free speech. Our right to sing and march and protest is one of the great pillars of our democracy. Sure, there are countries where such freedom isn’t granted, but it’s not a model that most Americans want to emulate. To deny Meryl Streep and “Hamilton” — to sneer “stick to your job” — is to deny John Lennon’s “Imagine,” and Public Enemy’s “Fight the Power.” It’s to muzzle Woody Guthrie and Bob Dylan, or Rage Against the Machine and Steve Earle. It’s to censor Marvin Gaye and Billie Holiday. So tonight, and maybe for several nights, I’m raising a toast to the protest singers. We need you. Belt it out. Help us process what we’re feeling. Speak for all of us. Unfortunately, it appears you’ll have a lot of material in the coming years.