By acknowledging that friend is slang for gay you also acknowledge that words are not necessarily bound by the definition that once existed. friend does not have to mean gay.
But it shouldn't have existed in the first place. I'm not sure what idiot decided to call gay people a cigarette.
The same way that 'gay' should never have become an insult, or the word for homoloveuality (although I admit, I use gay instead of homoloveual a lot). It doesn't make any sense - it's supposed to mean happy.
It's like:
"You're really lovey."
"What?"
"Oh yeah, forgot to tell you - I decided to change the meaning of lovey. It now means hilarious, okay?"