Not just from this thread, but I honestly don't think I've ever seen a site where the "its all about me and only me" attitude shows itself more. The parents being talked about in the past few pages work hard and use money that is just as good as any of ours to buy their tickets. The true problem lies with the airlines who chose to charge for anything but a middle seat, not the people who choose not to be suckered into that game. If anyone has a problem with the fact that they are stuck next to a 4 year-old then their problem is with the airline.
I don't disagree with anything you've said (except the "its all about me and only me" part). If someone's 4 year-old were seated next to me, I would take it up with the airline and, indeed, in a somewhat analogous situation (parent had usurped my seat before I boarded and whined, "what am I supposed to do?" when I said I wasn't interested in switching my E+ window seat for her E- middle), I did exactly that. I called over the FA, explained the situation, and she offered the parent the option of moving or deplaning. The parent and child (actually children) were deplaned.
It's not all about me. It's all about not imposing on strangers, and expecting that they won't impose on me, at least not without a damn good reason. "I'm flying with kids," doesn't remotely approach being a good reason. "The airlines don't care about flying families," doesn't remotely approach being a good reason.