Well, considering the kids at D.W.'s preschool, let alone D.W. herself, didn't even know what it was they were saying, naturally, they wouldn't know what kind of context to use it in... notice not only do they say things along the lines of, "No, you're a *bleep*!", they also say, "You look like a *bleep*!"... so yeah, it doesn't make sense to use it in those contexts, but the fact the those little kids don't even know what it is they're saying, THAT makes sense.
And Rocketburn, being a producer myself and knowing a few things about production, you would be surprised by how somethings are done when it comes to the soundtrack, and sometimes, somethings are achieved simply by pushing buttons... heck, back in the old days of sitcoms, the laugh track was added via a typewriter-like machine containing tape loops hooked up to the editing equipment, and during the editing process, when a laugh was needed, a button would be pushed to cue up a laugh.