If one defines "gay" as a behavior (i.e. people seeking sexual relations with a person or persons of the same sex) I would want to argue with that proposition, since not all sexual behavior is equally respectable.
BUT if one defines "gay" as (how shall I say) a kind of innate personality type, I would agree with their point of view. In other words, human dignity is an intrinsic value of all human beings, gay or straight, born or unborn.