When Ted Cruz told the audience at the convention last night that they should “vote their consciences” he was booed as well. Was it because they didn’t believe in that concept? Of course not. In that context they were expecting an endorsement.
Likewise with that band. They were performing at a charity and some in their audience didn’t want to hear their political preaching. They were booed because they didn’t have the graciousness and class to keep their politics out of an event where they really were not appropriate.
Under normal circumstances this wouldn’t gain much traction.
But when the GOP nominee’s rhetoric and antics have already been compared to Herr Hilter and a wide swath of right wing, hate group organizations including the American Nazi Party and the KKK have enthusiastically endorsed said candidate, it’s going to be noticed.
Trump’s GOP has become a white identity organization.