The reason you don't see
lesbians all over the place is that society has made it acceptable for women to
hold hands or hug each other, while for men it still looks out of the ordinary (at least where I live). I know that in
San Francisco and other places, it's normal to see men walking down the street holding hands, but in most other places, you don't see many men holding hands, and if you do, you'll assume they're gay.
I have walked down the street holding a friend's hand at least a thousand times. I have hugged a friend in public many times. And no one ever assumed I'm a lesbian. I know my male friends would NEVER walk hand in hand. And they wouldn't hug each other on the street, I'm sure.
So it's society that's made you blind to lesbians. What do you want them to do other than display regular affection? When a lesbian couple walks down the street displaying the same affection as a straght couple, you assume they are just friends. If a male gay couple did the same thing, you'd label them as gay. You don't really see any couple "get down" in the middle of the street.