Honesty, I think it would be fairly easy to figure out.
If it is derogatory - homophobe.
If it points out an idiosyncracy, and makes fun of it - queer, or at least not homophobe.
In my experience, bgoted people make jokes that insult and/or demean those people they hate. It is not done primarily to be funny, but to hurt and demean. Making it funny just helps spread it around.
Huh, you know maybe knowing the origin of the joke affects how I determine whether it’s derogatory or not?
I did not think about that, but looking back, seems like an easy pitfall.
Good point.