I'm gonna give you my take on this very valid question.
People are coming out younger and younger. So they are more unsure of themselves. That is reason number one.
Reason number two is that the public is still this vague and anonymous thing that basically puts homosexuality at the margins in not out side the borders of acceptability.
Then of course there is this, that for every one who comes out there is a unique story. As an Indian lesbian believe me my coming out was a cake walk. Many people assume that its harder in Asian communities.
I say its the unique characteristics of the story. I came out to my friends before my family.
The fifth thing I'd like to say (I hope you are keeping count) is what I told my sister when she worried over my life being hard and society not accepting me. I said: "I don't need acceptance from society as much as I need it from you."
Saying all this I'll conclude by saying it really is getting much better since the card catalogue days in my high school library looking up sexual deviance.