Earlier quoted context omitted.
https://en.wikipedia.org/wiki/LGBT_linguistics#Accents_of_En...
I'm aware of the trope. I've yet to meet anyone that adheres to it, though. Always thought it was just one of those things that Hollywood overemphasizes to "other" gay people.
Regardless, I think the point of collecting these stats is to make sure voices of people that might normally be under-represented in a uniform sample of a relatively small size can be corrected for. These are common stats to collect in surveys for similar reasons.
[0] https://www.sciencedirect.com/science/article/abs/pii/S00954...