Point (a)
Of course he would of come out sooner if society was accepting, but you have to assume that the reason why he didn't come out was because of social norms etc, when there are other factors that I've mentioned, accepting yourself for who you are first.
Points (b)
As people of an older generation didn't grow up with being around gay people and not be educated that there's more to people's sexuality than being straight etc, that there's different ways of life. They would be less accepting of gay people.
And if those people keep a closed mind and have kids they could pass their (I wouldn't say intolerance/ignorance) but they would pass their non understanding to their kids.