Well there is obviously an elemant of power abusing in the case of the Cabin crew member. A total lack of diplomacy skills is very much apparent and I reckon this lawsuit has more to do with that then the actual rule.
The thing is, I was always under the impression that this rule was only brought in by BA as a result of some wider european law or industry standard practice. We had the exact same rule in Aer Lingus and even Qatar Airways when I was with both of those.
Now I know kids are not always a precious as they come across. I was actually working a flight where we had a very demanding and down right rude UM travelling with us who even threatened to accuse the female crew member looking after her of "abuse" if she didnt get what she want (A seat up in Club is what she wanted...can you believe that from a 9 year old?). Needless to say we had that little madam brought down a peg or two very quickly but to any men sitting next to a UM....Just be very bloody careful about what you do or say when sitting next to a kid. These rules are as much about your protection as they are the kids.
However I do agree that kids are at just as much risk from female passengers. We just have to look at the recent news stories in the UK to know that!