You continually compare florists and cake bakers to performing artists. Performing artists are subject to entirely different laws (yes, they pass the “creative and artistic” test that florists, cake bakers, and public accommodation businesses do not).
Even the florist at the center of this debate conceded that if she supplied flowers for a Muslim wedding, or an atheist wedding, or any wedding except a same sex wedding, it would not be interpreted by anyone as her “supporting” Islam, atheism, or whatever.
Also worth pointing out — a performer is center stage during the actual event. A florist or a cake baker is not. If they are required to be at the site for setup (and they aren’t in all cases), they are still there before the actual event occurs.
And you can disagree with the court all you want to, but they didn’t consult you, did they?