https://www.reuters.com/article/us-facebook-cambridge-analytica-factbox/factbox-who-is-cambridge-analytica-and-what-did-it-do-idUSKBN1GW07F
they stole millions of people personal data without their permission, analysed their fears and targetted them by playing on their fears to vote in a particular way. you may well say that has been going on a long time but you are wrong. in the past political parties could use your data without your permission.
secondly they actually perverted democracy so much that they managed to get young people actually not to vote by starting a movement to encourage people not to vote and targetted the opponents of the party that hired them.
this is no ordinary situation. you can claim that we have been having wars since the begining of time but using nuclear weapons is not just another form of war.
they claim they deleted the data. anybody who believes that is just plain stupid.