I think both the parents and TSA share the blame for this going downhill. Parents most definately need to prepare children for security and not freak out if the child has to get secondary screening. Both my children have had secondary at least once(DS was 6 months old his first) and because the TSA and myself were very calm and the kids knew this might happen, they didn't think twice about it.
And when DS was very young and had a "blankie". We just told him it was going on a fun ride and we'd see "him" in a minute. Easy peasy. Some TSA may need more training in making things like this bearable for children.