Sing at a Reform wedding

Tzitz Eliezer (Part 17, Section 52) – explicitly writes that participation is prohibited, even as hired musicians, because it is seen as support and encouragement of a severe prohibition.
• Rabbi Ovadia Yosef (Yabia Ommar Ch. A.H.E. Ch. 15) – rules that playing or singing at such a wedding is prohibited, because it generally “aids the hands of transgressors” and gives public kosher to the forbidden thing.
• Rabbi Moshe Feinstein (Igrot Moshe Ch. A.H.E. Ch. 4, Section 22) – prohibits any active participation, even as a service provider, because it is seen as consent

https://he.m.wikipedia.org/wiki/%D7%A8%D7%92%D7%A0%D7%A1%D7%91%D7%95%D7%A8%D7%92%D7%A8

I don't think he intended to ask in order to attack other sources.
The question was whether there is a prohibition in this, and the rabbi would have been expected to explain why he thinks there is no help in this.
The rabbi's approach is also known, in that a rabbi is required to bring the dissenting opinions in his answer so that the questioner can decide how to proceed…
I would be happy to hear, then, why the rabbi believes there is no help here

This is a troll that should have been deleted. And Linkek Tirgitz is great. But Regensburger was not originally a troll, but a trigger for scholarly discussion.