I mean the principle of the concept of that sort of prejudice as a whole, whatever form it may take.
The list per sé is pretty useless, I believe.
But yes, it's damaging/dangerous in the sense that it continues the idea that being gay is "a problem", and that "fearful" parents could transmit that message to their children or somehow force them to "intervene".
The "song" is worse though. It's a clear case of homophobic abuse.
Can he be sued?