It's just the era that people are raised in. Back in the 40's/50's/60's, homosexuality was seen as extremely taboo and was never a topic people felt comfortable to talk about openly. Gay people had to basically keep it to themselves.
As time went on, people are being raised in more 'tolerable' environments. Religion is dying down a bit (which played a huge role on how people viewed others who they perceived to be different), people are getting more educated, schools and organizations are embracing different sexualities and diversity, and there's less pressure for people to conform to the 'norm'.
In other words, people just don't give a s*** anymore and aren't scared of being their true selves