Helping raise a lot of kids, a LOT of kids start “touching” themselves at very young ages. Why? Because it feels good. It’s not a sexual thing either, it’s just a child exploring their body. The same way an infant and toddler find their body parts (fingers, hands, feet) and start using them (grabbing, waving, walking). I haven’t gone to the site myself but if I were to read that I’d think the author was trying to say we shouldn’t discourage or reprimand children from touching themselves. Just let them know that it’s something to do at home, not out in public, and that it’s perfectly fine.