>Pls give me arguments against segregation
The implications of segregation appear to be a form of legally sanctioned no contact between communities despite living in the same country. By using different water taps and sitting on different places of the bus it could form a caste system and a contraction to the democratic principles whereby a nation stands. Another aspect of that would be that the government criminalised one community over the other despite the African-American community being liberated from slavery and their descendants. Geographically, it may have the effect of balkanisation as one community neglected by the government and institutions, even oppressed may instigate a breakaway. Attempts to demonise and slander one community over the other would be less checked for their validity as contact between each other has been effectively criminalised.
Segregation in the Southern USA was protesting the defeat of the Confederacy by the Union and the abolition of their property: their former slaves now as free citizens. It seems the Southern USA had sought to retain legislature and process that would impoverish the the former slaves now free citizens by sanctioning them from the society the rest of the free citizenry more or less enjoyed like jobs, medical attention and housing. Very likely the sanctioning was done to force the African American to return as slaves to their former slave owners rather than suffer the imposed misery.