Entertainment & Politics: when to stand up and went to sit down

I remember when Bruce Springsteen angered many of people years ago when he took the stage and spoke out about the killing of an unarmed African named Amadou Diallo who died in a hail of 41 bullets from NYPD. Now in 2016 Beyonce seems to have ruffled many'a feathers with her Superbowl 50 halftime performance. I don't know what the big deal is but then again I do and my question is should musicians, entertainers or athletes step up and voice their opinions when it comes to political issues?