Streisand Effect. I agree with your opinion, if they are hired and paid to preform at a venue, then that type of work should be free of personal message or bias.

If they had paid for use of the venue(basically a tour or show) then that would be a platform they are welcome to explain their message.

That being said, no idea why your are being down voted, you are having a friendly and respectful conversation here, and even I can see merits in your debate.