You must not have kids. Most 18 month old kids act just like the one on the video when you want them to sit quietly in one place. One of my kids was perfect on planes and my other acted worse than the kid was at the news show, but she would throw a fit for 10-15 minutes and be fine, or just fall asleep after that. There is not much you can do about it and its not bad parenting, kid throw fits.
If the flight attendant is so worried about her safety brief then she should just go back and ask all of the passengers if they were able to hear her. If they couldn't then she could simply brief them again at their seats.
We don't know the whole story, but even a kid that is kicking and screaming should not be kicked off of a flight. My guess is that the flight attendant had a long day and was a little edgy. The mother probably said more than she would like to admit and really ticked the flight attendant off. I know that I would have told the flight attendant where to go if she told me my kid needed medication and the cops would probably have to drag me off the plane.
Comfort???? If you want comfort don't take public transportation (or buy some earplugs).