Why did he do it anyway?
Science as a practice tends to ask the hows and if-thens waaaay before asking the whys. (businesses ask why. Customers ask why. The way we practice science is all how). If the need to know or prove something was strong enough, and the scientist in question had the power... well.
What should be done?
If we are talking future preventative measures? I think we are out of hecking luck in keeping all of humanity on the same page. Nothing is going to stop something like human curiosity forever. However-- I think if we could marry art or thoughtfulness or some sort of humanitarian nobility back into the very idea of science, it would help.
If we are talking justice... public humiliation and denouncing goes a long way-- which is what the Chinese Government is already doing based on the assigned article. Any problems the two girls face because of the missing protein pathway need to be on his paycheck and on his head.
Compare this to other unethical science projects.
Welp. Coulda been worse. It is a sort of medical treatment, but the method was... hmm. bad. Dumb actually. Thoughtless to the livelihood of the individuals he made. Its not really comparable to the Henrietta Lacks case (in which a man profits off of a dying woman, a natural tragedy, and doesn't compensate the family). Its not comparable in severity or motive to to project 4.1 or the Nazi doctor stuff (in which suffering is purposefully inflicted on powerless individuals to see what that suffering does/what can be done.) Of the I think this is actually closest to the the Tuskegee Syphilis Study, being that the science involved was to learn how to cure future generations (motive), but even then, the sins of the Tuskegee Syphilis study lie in taking advantage of ignorance and concealing information, and later, a treatment. Of the information I know ( because I don't actually know if Jian-kui concealed any information. He might have.) the rest of the similarities of the cases of Jian-kui Gene Babies and Tuskegee Syphilis study are superficial.
Public opinion of science going forward? (sidenote, I don't really know what "give an example" means here)
China is in the doghouse, pubic opinion wise. But on the whole? it was only a matter of time until someone screwed and screwed up with the human genome. I am not surprised, and it could be worse. And if what we did in project 4.1 didn't do anything I really don't think this will have much of an impact either.
Other then having things that are more over the line swept a bit further under the rug by the people doing them.
Li J ru, Walker S, Nie J bao, Zhang X qing. 2019. Experiments that led to the first gene-edited babies: the ethical failings and the urgent need for better governance. J Zhejiang Univ Sci B. 20(1):32–38. doi:10.1631/jzus.B1800624
Lipset D. 2016. Nuclear Savage: The Islands of Secret Project 4.1. Contemp Pac. 28(1):270–273. doi:10.1353/cp.2016.0001. [accessed 2020 Apr 19]. https://www.videoproject.com/Nuclear-Savage-The-Islands-of-Secret-Project-4-1.html.
TED-Ed. 2016. (6) The immortal cells of Henrietta Lacks - Robin Bulleri - YouTube. [accessed 2020 Apr 19]. https://www.youtube.com/watch?v=22lGbAVWhro.
CDC. 2013. Tuskegee Study - Timeline - CDC - NCHHSTP. :1. [accessed 2020 Apr 19]. https://www.cdc.gov/tuskegee/timeline.htm.