why is judaism better about keeping out the losers?

[Dana]

 On the contrast the one class with a non Reform Rabbi was full of respect and admiration for the Torah, and really solid concepts like one God, mitzvot, tikkun olam. 

Just a question you may be able to answer.  I understand one G-d and the mitzvot are solid concepts within Judaism. However, how and when did tikkun olam become a solid concept in the Torah? If that is what you mean?  

Outside the Aleynu prayer, the line "to perfect the world under the Kingdom of G-d," there is no mention of tikkun olam in the Tanach.