"Stephanie Fennessy, director of the Giraffe Conservation Foundation in Namibia" says that the behavior described as "gay" in giraffes is usually just a display of dominance. So it's uhh not considered affectionate by Fennessy.
So at least one expert says that 90% fact is misleading. I was curious enough to read one article but curious enough to dig more.
A lot of animals that do male on male action do it for the experience and to better themselves for whenever they find a female mate to better pleasure them...