Having read everyone's posts, I think that each person has a valid point. Personally, I have no trouble with FC passengers and try to fly in FC as much as I can!
I do at times have problems with children. On one flight from Hawaii to LAX, a gentlemen with a large 4 year old had both sharing a seat. The child was in front of him face up against the seat in front of him. The child was quite pleasant, as the father was. However, 5 hours in coach, with a child in back to back seats in coach is NOT a place for a child. As the flight progressed, the child managed to spill my food, and whack me in the eye. My legs could barely fit in the space the child was crammed into!(And I am 5'3 and we all know how bad the space is in coach) If the child had his own seat, I doubt there would have been any problems.

I thought that this was something that should have been addressed by the FA's. I wrote the airline, and they said that there were certain weight limits, which obviously had not been attended to in this situation.

Another experience that I had was on America West(not one of my favorites by far). I was sitting next to an 11 year old traveling alone. She was a great kid and very well mannered. The flight was delayed and we were all stuck at the gate, not being able to leave(this is another story in itself). The child's parents had paid extra money for her to have some airline escort. NO ONE paid attention to the child. I took her with me, and called her parents, although I was afraid they might think I am some murderer, but I wanted to let them know what was going on. I then approached America West staff, and explained to them that she was not attended too. They whisked the girl away, and I saw her 6 hours later when we returned to our seats.
Apparently, they had taken her and other children to a separate room, and they watched TV, they were NOT given anything to eat. The poor girl was starved. I asked the FA to bring her some food, which she did.
As adults, we are assertive in getting our needs met. Children traveling alone, do not have this skill. I think the airlines should have treated the kids better and with more care. I also wrote America West regarding this, and recieved somewhat of a benign reply.
I guess my point is, both parents and the airlines can be at fault.