[Daffy]

from the dictionary, definition 3 applies:

GAY
1. Filled with or inspiring mirth; merry; sportive.
2. Brilliant; showy.
3. Loving pleasure; wanton.

WANTON
1. Dissolute; unchaste; licentious; lewd; lustful.
2. Recklessly inconsiderate; heartless, or unjust; evincing a malicious nature...

Therefore, to be GAY (homosexual) is: Loving pleasure; dissolute, unchaste, licentious, lewd, lustful, etc. And so they label themselves.

[onedoug]

My trusty 1957 Webster’s, “...4) wonton; licentious; as, a gay dog.”