Because he says some things you personally disagree on or have the willingness to be outspoken on sensitive socio-political issues that might irk or piss off some in your audience? That takes guts.
It doesn't just apply when celebrities express ideas you support or believe in and feel that its okay or justifiable, but criticize the other side when they do the same?
I don't agree with everything someone like Sean Penn, Tim Robbins or Susan Sarandon has been outspoken about over the years but I respect them as being great actors and their willingness to put their careers, reputations, and credibility on the line even if that meant in Penn's case supporting a oppressive, semi-autocratic, power-grabbing caudilo in Hugo Chavez's Venezuela during the 2000's up until his death and how his country, and its overall economy fell apart after his death.