^^^My experience has been different. For me I can appreciate an older scene, which is what I was expecting on my first visits to the city and when I first moved here. I have been pleasantly surprised by how young the scene actually is, but as someone who lives here I know I don't need to go to the Mix or Q Bar right in the Castro to find my scene. I think between Castro's bars/clubs (which stretch all the way down to Church St...there must be ~20, been to Hi Tops by chance?), SoMa's/Mission's/Potrero Hill's clubs, and the "mixed" scenes throughout the rest of the city, there are many more young (and attractive) guys here than the rest of America stereotypically gives credit for. I moved here from Atlanta which is supposedly known for its young and attractive scene, but I'm much more thoroughly impressed by SF and it's a million times easier to find a datable guy here than there. I think the scene is only exceeded by a few cities, and for me it's not just age and looks, but job and head on shoulder. LoL that eliminates Atlanta, Miami/Fort Lauderdale, LA, and tons of other places known for their "scenes", narrowing it down to basically NYC, Chicago, Minneapolis, DC (though douchey crowd!), and Seattle.
Anyway, in the Castro you can find hoards of young guys and hookups in Badlands, Toad Hall, the Cafe, Lookout, Hi Top, arguably Blackbird for some quality guys, and then if you want to go clubbing in SoMa or wherever there is plenty of that as well throughout the city. The population itself is concentrated in Castro, but also pretty evenly spread out throughout the city. I live in the "least gay" part of the city (financial district), and yet I have a good friend both 1 floor and 2 floors below me and in surrounding buildings. Another one of my friends wants to be roommates and live in Lower Pac Heights or Russian Hill, which are "straight" areas with plenty of gays sprinkled in.
I just did the math though - I could so easily be roommates and split a 2 BR in 38 Dolores, which of course I wouldn't mind doing

They start under $4000! That's a bargain compared to what I pay to be in a cramped, dated studio now - dear Lord!!!