The legal system is unfortunately set up such that there is a significant burden (time and cost) on defendants, even when cases are brought without merit.
In that way, the legal system can be "weaponized" and public employees can be influenced to act a certain way under the threat of a sea of PERSONAL lawsuits. ...something that seldom happens to individuals.
For that reason, immunity was created. I think we'll see a very sharp increase in lawsuits as a result of this change. ...and a lot of resignations. I wouldn't be a police officer if I didn't have immunity. At the very least, I would refuse to work shifts/neighborhoods with high crime.