4) To know about Manu, you have to read it first. We cannot discuss in so little space but let me tell you Manu law is one of the finest Law in human history but Congress Party has wore Secular Mask so they will not accept it public openely simpy because it has come from Vedas and belongs to HINDISM.
5) Caste system has made for our society benifitial and based on the JOB if you go back to history you will find it. And this system was so liberal and open that everybody had right and choice to choose their own Caste by choosing their JOB. It called CHATURVARNAs!
6) Who told you all RSS chiefs are Brahmins, i think being yourself DALIT you see everybody as Brahmin around you....change the way you look brother!
7) And last answer for your last question - Dalits treated like animals in only few regions and by only perticular social community like Jamindars (Land Lords) who had major Dalits servants at home or fields. Its very sad but for that one cannot blaim on HINDUISM or its any organisation like RSS.
Hope my friend you satisfied with my answers if not then no wonder...you yourself don't want to get convinced and accept the truth like all other your DALIT brother.