It's hard to argue with science. I'm quick to defend the current generation from undue condemnation, particularly when it comes to choice of dress, but there's no real rebuttal against the idea that verbal abuse is detrimental to healthy brain development. No arguments there. I suppose the logical followup to the article is, "What do we do about it?" I can't think of one realistic way to begin a widespread cultural change.
I can't say if there are any "chemical" question about politesse. My very first answer is "no". If you get a behavior as good, this is polite.
Though it is possible for people to overcome trauma and rise above the abusive behavior, but children need time and life experience to see that there are other ways in the world. When they are adults, however, they are responsible for their own actions.