The whole Rabirius thing is a lot more complicated than Heraklia makes it sound. To begin with, Caesar was iudex quaestionis at the time, which meant he was in charge of the courts. As such he conducted a large number of murder trials, many of which were against people who had profited from proscriptions during Sulla’s dictatorship even though they were supposed to be exempt from prosecution.

Suetonius says that Caesar bribed someone to bring a charge of treason against Rabirius and that Caesar was then appointed by lot to pass sentence on him. What’s really significant here is that Rabirius was not tried in a normal court, but by an ancient and practically obsolete form of trial called duumviri perduellionis. Essentially that meant that Caesar and a colleague conducted the trial and the only form of appeal was directly to the people. Suetonius says that Rabirius made such an appeal and was helped by the harshness of Caesar’s judgment against him. Somehow I have a hard time seeing Caesar misreading the people so badly, but this was still rather early in his career.