The photograph, by Alfred Eisenstaedt, appeared in Life Magazine. Here's some Life text about the scene on V-J Day:
Booze flowed, inhibitions were cast off, there were probably as many fists thrown as kisses planted; in other words, once the inconceivable had actually been confirmed and it was clear that the century's deadliest, most devastating war was finally over...That text, quoted at the top link, which goes to NPR.org, comes from a Life webpage written long after 1945. That page includes this parenthetical:
[I]n the giddy and even chaotic first few hours after the announcement, people naturally took to the streets of cities and towns all over the country. And while some of the merriment was no doubt of a quieter, G-rated variety, it's hardly surprising that countless grown men and women seized the opportunity for cathartic revelry, giving vent to joy and relief as well as to the pent-up anxieties, fears, sorrows and anger of the previous several years.
(It’s worth noting that many people view the photo as little more than the documentation of a very public sexual assault, and not something to be celebrated.)The words "little more" imply Life's concession that the kiss was a sexual assault. And if you read the text quoted at NPR closely, you'll see how oriented it is to explaining and justifying our love for the photograph.