Any idea of what percentage of the population this applies to? - I have no idea what percentage this applies to.
I'm only going by what I've seen and heard myself, plus what I've read.
The Australian swimmer Ian Thorpe came out as gay a few years ago. He said it wasn't easy coming out. And he also said something like 'when I was at school there was a stigma around being gay, being effeminate'.
The percentage might be low but is still part of traditional masculinity.
Usually, school kids grow out of such juvenile nonsense.
Western society is actually very gay-friendly, relatively speaking.