First, you're entirely right to be pissed, this was douchey, stupid and a fair bit homophobic.

But what you should actually be doing is telling them how you felt instead of ressenting them and cursing them with other gays.

First, people do fuck up, you might not want to forgive them but I think it's always good to hear the other side of a conflict (here, mostly an apology once you've explained why and how you're pissed).

And where I think you're missing the mark is when you don't take this as an opportunity to kindly and not agressively explain to them what being gay means and why this is not cool for them to do that. You might be annoyed to have to do that, but you can't realistically expect people who absolutely know nothing about your world to understand everything about it from an outsider privileged (as you said) view. Don't put them down, include them to this knowledge and see how they react (if they brush it off or understand and apologize)

The douchey and lame manipulation part of their joke was idiotic at best, and weither one forgive another of these is entirely up to each individual. When it comes to the homophobic part I tend to think it's mostly forgivable because they just... don't realize and it's a good thing that you're here to make sure they don't do it again and to sensitize them more to the challenges lgbtq people experience.