In the original Civ, every leader had an aggression rating ranging from 1 to 10. Gandhi, being who he is, was of course set to the lowest value here (a 1). However, when he reached mid-lategame he was set to adopt Democracy which, among other things, reduced an AI's aggro rating by 2.

Because of how bit values work, instead of setting his aggression to -1 or 0, it looped around and put him to the maximum value.

So at the point in the game where nuclear technology is being developed, where the most aggressive leaders in history are sitting at a 9 or a 10, Gandhi is at a fucking 255.

I get that reference.