Diyya (Blood money compensation) Credibility ?

[Hassan Afzaal]

Salam Everyone!
Few hours back, I acknowledge about the Islamic jurisprudence law ruling in Saudi Arabia named "Diyya" or blood compensation money. According to this law the murderer could get rid of beheading or capital punishment if he/she manage to pay financial compensation to victim's heir. Furthermore the amount of compensation has fixed by state. e.g
For Muslim male = 300,000 riyal
For Muslim female = 150,000 riyal
For Jews /Christian= 75,000 riyal
(These above compensation rates are not taken from authentic source, just to give you an idea)
So my query is, how Islam can tolerate this discriminative law? Which violates following fundamental rights among:
1 Rich Vs Poor
2 Muslim Vs Minority
3 Male Vs Non Muslim
I am neither the law student nor the Islamic jurisprudence is my elective. So its my humble request to the law students and seniors, to make me understand about the sense of this law. How the giant Muslim country/countries can implement this law? What image they are representing to the rest of world?