Ummm actually sounds like the TSO's got it right
IF a child is a selectee, AND a parent is a selectee, THEN both the parent and the child have to undergo Selectee screening. That is directly from the SOP.
The SOP doesn't say both parents have to be selectees. Most Supervisors would interpret the SOP language as, " if one parent is a selectee, then the child must be treated as a selectee. " I suppose it would be possible to get a child through with a non-selectee parent and then have the child deselected, without informing the TSOs that the other parent is a selectee. Personally, I am not too concerned with 1 year old selectees, whether their parents have selectee status or not.
CHildren cry for numerous, numerous reasons at the checkpoint. Children often think you are TAKING their toys, if you tell the parent a toy needs to go through the xray. We all know they are getting the toy back, but the child is apparently unaware of that. Yes that is slightly amusing, and might get a chuckle from a TSO. I don't think its grounds for anything to happen to the TSO.