I was thinking (hoping) the lack of musicians willing to perform was based on their not wanting to normalize and celebrate a dangerous full-blown narcissist at the helm of a world power.  A thin-skinned narcissist who has the ability and personality traits that can destroy the world with an impulsive crazy decision of a minute, if he gets enraged by a perceived or actual slight.   Not to mention the many  similarities between his authoritarian/autocratic, dissembling/lying ways, and those of the rise of the Third Reich.   

To participate in celebrating this Twit, or to "give him a chance" is to enable/cooperate with that.   And that's what despots count on.    The pressure by supporters for everyone to cooperate, "get along", "give him a chance", till liberties and freedoms are fully limited and power is seized by the narcissist and cronies.   Look at the history of dictators around the world.

Anyway, to your point:    I was hoping that the lack of musician participation was based on not wanting to legitimize that, rather than losing CD sales....