I have heard that music is one of those things that penetrates directly to the neshama, the singer and perhaps musician as well have a direct influence that we cannot filter out. In general that is the danger of “goyisha music”. The concern here is that at the time this particular artist had the machshavas that are now being expressed, if so then these underlying feelings will be conveyed in his music.
For whatever its worth, I stopped listening to his music after attending a concert of his. The crowd at the concert missed the message of the music, mixed dancing being the *least* of my objection. I had no expectation of him stopping the show or preventing a certain type of crowd, however, if his music had been of pure intent then perhaps the crowd would have filtered itself, by being affected by his music and message.
It saddens me that such a public figure, so well known for his yiddish appearance, would choose this path. I hope his family is strong and has the proper people around them to help support them. And for their sake and the sake of all am yisroel he finds his way back to where he needs to be.