I think it would be difficult to think of Naruto and Sasuke as real people in the first place. Most of their depth/worth exists exclusively in fandom, IMHO, so I doubt their being gay would be all that thought-provoking. It would either be "okay, who cares?" or "what the fuck????" But then, this might just be unwarranted pessimism, because I'm still :EEEEE at Naruto for the Leaf Splitting arc and the Pein arc, and :EEEEE at Sasuke for, uh, well. Whatever it is he's being doing. So it's hard to imagine them being perceived as a force for social change.

Depending on the age of the child, though, I don't think they'd make the distinction between Really Good Friends and Gay Couple (or Het Couple and Friends, for that matter. I didn't, and often still don't). Even if there was A Kiss. I guess it's hard to judge from my perspective, though, because my parents and my family and most of my friends don't categorize relationships that way. (The one who does would likely just chalk Naru/Sasu up to especially amiable platonic love.)