Anyone care to explain what's with the "Off-topic " part?

I think it's something about that danbooru is NOT a hentai board rule. But even if it's porn, the art is good so I don't see any problem in adding it here((

According to what passes for what's left of actual rules whenever the mods can agree to enforce them with any degree of regularity, as opposed to mere whims of people with power arbitrarily with no consistent standard that can actually guide future user behavior, Danooru is an anime art site, and therefore some people at least try to enforce the idea that things should be related to anime in at least some fashion, whether by being drawn in anime style, being a Japanese copyright, or maybe having an eastern artist make it. Other mods prefer to have no rules whatsoever so that, again, it's just arbitrary whims and nobody can tell what is or isn't allowed until a lot of their stuff gets flagged (unless it doesn't because they're given unlimited uploads...), which just leads to more drama than having a consistent set of rules in the first place.

Overwatch isn't anime-related on its own, and I've seen some backlash to so much of it is getting posted here. (Having a Patreon and Deviantart ad in the corner probably doesn't do it favors, either...)

Beyond that, I'm guessing it has more to do with the child post's ahegao than this post, in particular.