—Deb, New York, via the Answer B!tch inbox
You answered your own question: Headlines.
Like your Answer B!tch, you live in a city where many lesbians are out 'n' proud and girl-on-girl kisses are old news. But across many huge corn-clad swaths of this great land, that kind of thing is just news. So of course Sandra Bullock and Scarlett Johansson are going to pull this stunt: They know it will shock and titillate millions of people—and deliver headlines.
Just like it did for the star who really started the trend:
And that's Madonna (Marlene Dietrich notwithstanding). Remember wa-a-a-ay back on a crisp fall day in the year of our lord two-thousand-aught-three? The MTV VMA Awards?
In a clear nod to Dietrich, who dressed in men's clothes and locked lips with a woman in her classic 1930 film Morocco, Madge donned a top hat and kissed both Christina Aguilera and Britney Spears.
The planet just lost it. USA Today's headline read, "Madonna, Spears, Aguilera shock at MTV Awards." (Some modern-pop historians may say that the onset of latter-day girl-on-girl kisses started with the 1998 flick Wild Things, starring Neve Campbell and Denise Richards. That theory is fine, too.)
Since then we've had Cyrus faux-kissing women in faux-raunchy live performances (and then making it clear they weren't actually kissing); Bullock smooching Meryl Streep at the Critics Choice Awards a few months ago, and then Johannson just the other night during the MTV Movie Awards; those two Russian girls who kissed each other a lot and then disappeared; and Katy Perry singing about how she kissed and girl and liked it.
Why? Because so many people talked about the Madonna/Christina/Britney performance, for one.
The other reason we're seeing all the girl-on-girl kisses? Well, yes, people talk about girl-on-girl kisses these days, but they don't really condemn them all that much, at least, not so much as they used to.
"The kissing of two major female celebrities onstage should come as no surprise at this juncture in our societal development," openly gay family law expert attorney Steven Knowles tells "Gay conduct, gay stories, and gay celebrities themselves are becoming increasingly prominent."
(Big difference, though, if you're a guy kissing another guy, though, right Adam Lambert?)
In other words, girl-on-girl kisses are great for (a) grabbing ink while (b) remaining wealthy, famous and popular. And, really, what other publicity stunt can claim the same result these days?