Any inappropriate behavior in the Concierge Lounge is disruptive to the other patrons, whether that be an unruly child, a loud guest on a cell phone, a group whose laughter carries through the room, or two doctors discussing their patients hysterectomy (and yes, I've experienced ALL of the above at Marriotts).
However, I've found that, in the Concierge Lounge, the attendants are usually very hesitant to say anything to the patrons on their own. Let's face it, everyone in there could be considered Marriott's best customers, both the offenders and those offended. I think it would have been unusual for the attendant to say anything to the parent unless someone had complained. The attendants are always very gracious and not looking for confrontation amongst their guests.
PTravel, apparently you did not indicate to the attendant that you were being disturbed. Apparently, no one else in the C Lounge did either. The attendant is not a babysitter and she is there for the comfort of the guest. Unless someone were to complain, I'd say it's highly unlikely that she would take it upon herself to berate a guest for their child's behavior. (And you can bet this isn't the first time they have seen an unruly child in the C Lounge.)
However, PTravel, it is clear you have no children. It's also very clear, from your many, many posts on this subject, that children bother you. Maybe you just seem to attract the unruly ones, for you have posted on this subject more than most. Maybe you just have a low tolerance for noise, or a low tolerance for distraction of any kind. Unfortunately, you will encounter children in a hotel, on a plane, in a restaurant from now until forever. It's probably in your best interest, for your own health, well-being and sanity, to find the coping skills that allow you to rise above distraction. Otherwise, the only one who suffers for it is you.