"We knew that we picked an unpopular cause to champion," Schlachet told the CJN. "And frankly, from a personal standpoint, I think it's important to represent unpopular causes because, first of all, it's what we took an oath to do, and it's completely consistent with my Jewish upbringing. We actually did a mitzvah representing this man."
A "mitzvah" — independent of its "bar" or "bat" — simply means an act of human kindness, a moral deed. Here's Weintraub's explanation.
We saved him from potentially lethal injection and 20 years on death row, which would have cost the taxpayers and the community millions and millions of dollars, and we spared the women the anguish and 'revictimization' of events.