An interesting little history by Wayne R. Dynes, which briefly goes over several writers throughout history promoting this misconception. Sample:
The scholastic theologian Albertus Magnus (d. 1280) held that the vice of sodomy was “more common in persons of high station than in humble persons.” This impression reflects in part the greater visibility of the doings of the privileged, and also the fact that, through their status or influence, the nobility could frequently escape with a reprimand for the commission of crimes which were subject to capital punishment when committed by commoners. This aspect of class justice has fueled social envy, leading to the demand on the part of the straitlaced middle class that the aristocracy be disciplined and required, for its part, to adhere to the narrow canons of petty bourgeois morality.
Probably need to take the opinions of scholastic theologians (apologists) with a grain of salt. What he’s seeing is a reflection of the material reality that religious prohibitions are tools of the ruling class to control the proletariat. The ruling class rarely subjects themselves to their own prohibitions, so therefore they felt more free to ignore the church whenever they felt like it. Homosexuals exist in bourgeoisie families in equal proportion to proletariat families. It’s an aspect of human behavior that has nothing to do with class. It’s relation to class has only to do with the fact that certain privileged classes are just more free to live their lives as they see fit.