I have seen this several times today on cm.
It strikes me as weird.
One, why is it considered immature? I don't get how age has anythign at all to do with it.
Two, I can understand why some may think it's gross, but on light flow days, it really is better to not use tampons, and what else should one use? Not everyone likes cups. And if changed properly (ie frequently) they are sanitary.