Interesting analysis of the Jedi Order and their place in the Old Republic:

The Jedi turn a blind eye to the existence of organized slavery on the Republic's borders until it suits the immediate tactical interests of Qui-Gon Jinn, and even then it doesn't look likely that the Council will work to free the slaves of Tatooine and other planets. It's none of their affair.

By the time members of the Council come face to face with the true enemy -- in the person of Palpatine -- they are too intent on seeing evidence of the Sith to recognize it when they find it. The Phantom Menace himself escapes, unnoticed while Yoda and Mace Windu pontificate about the nature of the Sith Way.

The path to the Dark Side is said to be easier than the Jedi way, closer to adult thought patterns and the everyday world. Sith masters don't have the luxury of stealing Force-talented children from their families -- the Sith spent centuries one step ahead of the Jedi, and caring for a baby would be a severe impediment on the run.
^{More at: http://www.space.com/sciencefiction/movies/dismantling_jedi_order_000418.html}