Your story completely misconstrues the intention of the guide, which is seeking to redress the current lack of representation of the LGBT+ community in the arts.
What lack of representation?
John Gielgud and Ian McKellen give us our 2% gay among the theatrical knights, Redgrave gives us the bi- we need for balance.
Or to be a little less obtuse about it, current population numbers tell us that 2 to 3% of men are gay, 1 to 2% of women are lesbian and some few thousand out of 65 million of us are trans. And someone, somewhere, wants to try and tell us, with a straight face, that the portions, percentages, among artistes are lower than this?