Seems like the alternative is equally dystopian though. If ex-presidents don't have immunity for their actions in office, then every ex-president will have to fend off a flurry of lawsuits and prosecution attempts by the opposite party. It would be an absolute circus and turn the office of president into a joke.
That's a false dichotomy, just allow the motivation for official acts to be taken into consideration for prosecution, and a lot of the problems go away.
Also, to reduce the hysteria of this, even if a president has immunity, committing an illegal act and using that immunity would still end up with a legal challenge and that would need to work its way through the courts. Would be a huge headache, and the Supreme Court could very obvious rule differently in a particular case, hinging on what is official and what is on official. I doubt the Supreme Court would look kindly on an assassination of arrival as a “official” act
Fitzgerald gives them immunity from civil prosecutions. That was mentioned by Sotomayor. Fitzgerald explicitly does not provide the same immunity from criminal prosecutions; specifically because the protections for a defendant and burden of proof are so much greater than a mere civil case.
