Pirke Avot 1:8- Rabbi Yehudah Loses His Sense of Judgment

After gaining a Jewish sense of judgmentalism and when one should give another a benefit of a doubt when judging others, you come across a verse like the one below (Pirke Avot 1:8) and begin to wonder what R. Yehudah ben Tabai was thinking:
יהודה בן טבאי ושמעון בן שטח קיבלו מהם. יהודה בן טבאי אומר, אל תעש עצמך כעורכי הדיינים. וכשיהיו בעלי הדין עומדין לפניך, יהיו בעיניך כרשעים; וכשנפטרים מלפניך, יהיו בעיניך כזכאים, שקיבלו עליהן את הדין.

Yehudah ben Tabai says: [When serving as a judge] do not act as a lawyer. And when the litigants stand before you consider them [both] as guilty, but when they are dismissed from you consider them [both] as innocent, provided they have accepted the verdict."

I'm not disputing the first half, the part where it says that both are equally guilty.  In order to be a good judge, one has to be objective.  Biases, bribes, preconceived notions, personal experiences, and assumptions can all get in the way.  To judge both sides on even ground is optimal. 

It's the other part that bothers me.  "When they are dismissed from you, consider them both as innocent."  Really?  I mean, really??  This first and foremost makes no logical sense.  The purpose of having a hearing is to prove one's guilt.  If they're both innocent, why take the time, money, and effort in such litigation?  It'd be a superfluous act.  I can understand where R. Yehudah is coming from in the sense that Judaism judges action, not intent.  Rabbeinu Yonah comments and assumes that he [the guilty party] has repented.  However, it does not [nor cannot] take modern neurology and criminal statistics into consideration.  There is no current treatment for the child molester.  Criminals have a propensity to be repeat offenders.  Some people are just beyond saving.

Judaism does believe in repentance, forgiveness, and a second chance to return to G-dliness.  However, whether it is a civil or criminal matter, someone has to be guilty.  There's just no way around it.  I'm hoping that R. Yehudah was trying to make sure we don't become jaded or have our experiences bias us in future judgments.  However, looking at Rashi's commentary [on the verse] that states that you should presume that both the litigants were not intentionally lying, this seems like a "bleeding heart" verse based in naïveté.