Just as there are gay men and lesbians who are promiscuous and are just interested in physical relationships, so too are there promiscuous hetereosexuals.
There are also men who want a secure loving relationship with another man, who they like having sex with, and lesbians who wants the same sort of relationship with a woman. Just like straight people who want a secure relationship with the opposite sex.
I've known gay people who have been in relationships decades long, lesbians who go through a wild phase of discovery before settling down on the opposite side of the world with their girlfriend... and straight people who've done the same WooHoo! thang and settled down with someone of the opposite sex.
The biggest mistake you can make is to think homosexuality is all about sex. It is no more all about sex than heterosexuality. Yeah, there's mad sex clubs for gay guys, lesbian pick-up bars... but as straight people have the same sort of things all it does is show that gay people are just like straight people apart from the liking people with the same naughty bits.
Just as there are straight people who talk about their sex lives (I'm sure some straight friends of yours talk about their sex lives jaguar), so too there are gay people who do that - and loads who don't.
Hell, I'm sure some people you know go home to someone of the same sex and you don't know.
The symbols thing makes me think of clothing styles. A friend of mine was refused entry to a lesbian bar once as she was wearing a pretty cotton summer dress. Apparently in some clubs, all lesbians are equal, but the ones in combats, army boots, crew-cut T-shirts with wallets on chains and short hair are more equal than others.