The simple answer here is because of slavery.
He stated that he did not feel like rejoicing because the people he fought against had fought valiantly and full of pride for their cause and never faltered. He did add that although he admired their strength of belief, he did believe that the cause they chose was the worst cause in the history of mankind and that they were in the wrong.
Answer:
The social, economic and political conditions in Russia, before 1905 was quite backward. Social inequality was very prominent among the working class. Workers were divided on the basis of their occupation. ... Workers had strong links to the villages they came from and this also caused a social divide among workers
The abbasid dynasty tried to make an empire founded on the equal
opportunity of all Muslims. The new rulers stopped the large military subjugations,
finishing the supremacy of the Arab military class. Under the early
Abbasids, the domain of the caliphs touched its utmost prosperity and control
and the Muslim civilization succeeded. Under the Abbasids, Islam turn out
to be a more varied religious because discernment against non-Arab Muslims finished.
The Abbasids also stimulated the capital from Damascus to Baghdad.
This transfer into Persian land permitted Persian administrators to hold significant
offices in the caliph's government.
