You cannot provide evidence that demonstrates that those men were engaged in anything other than strong denial, unless they weren't gay in the first place. My sister was almost exclusively with women from age 20-28, but now she is happily married to a man and has a kid. She didn't identify as gay though.
I think the labeling scheme also confuses things. It creates weird expectations. My personal view is that sexuality is much more fluid. I identify as a gay man and have only been with men. Even though it seems impossible to me now, I may some day decide to be with a woman. That wouldn't make me "cured" or something.
All this shows is that sexuality is complex.