For the most part, the British did not treat the Indians very well when they took over India.
There can be many different reasons to explain the poor treatment of Indians at the hands of the British during the take over of India. One reason would be economic. Britain saw India as an investment opportunity. British control over India guaranteed new revenue streams. They were able to take cloth, spices, and others items from India and sell them for profit. English exports from India were produced in large quantities to guarantee economic growth. The desire for wealth helped to drive the British control of India. In the process, many British people treated Indians as a means to an end.
I think that another reason why Indians were mistreated was because of a culture clash. The British came to regard much of Indian culture as "backwards" or "superstitious" or "uncivilized." Such views enabled the British to denigrate Indian culture and label those who adhered to such beliefs and practices as inferior. The British failed to understand the nuanced cultural reality that defined so much of India. They did not account for the level of divergent social, cultural, and religious reality that defined so much of the subcontinent. Many British viewed their purpose as "improving" the condition of India This process resulted in the relegation of Indians to the margins of many aspects of life. Such beliefs led to a social order that placed the British at the highest of positions and kept Indians subservient. Exclusionary practices, force, and political manipulation were means used to silence Indians while maintaining this hierarchy. This became another way in which Indians were mistreated at the hands of the British.