Explanation:

US is a purely federal country and the constitution is more like an agreement between the states. The states have combined to make a country and hence called "The United States of America". India is called as a "quasi-federal". Indian states are made by division for administrative convenience. (Though some states are based on linguistic grounds). Hence the first Article of the constitution defines the country as "Union of India" rather than "United states of India". The country comes first and the states comes second. The parliament can change the boundaries or divide and unite the state as per convenience & demands, unlike USA where states are indestructible. USA has the concept of double citizenship where a person is the citizen of the country as well as of the state having some specific rights given to citizens of that particular state. In India there is no concept of double citizenship (except some specific rights for citizens of J&K).
Hence a 'state' as a concept is weaker in India compared to USA. The people are supreme in India and not states. The people are given equal powers by assigning them seats based on the population. If equal no. of seats were given to states then it would have undermined equality among people of the country, who have equal rights. The share of power (seats) per person in larger states would be less compared to smaller states. Hence no. of seats assigned to states are unequal in Rajya Sabha compared to the senate in USA which gives 2 seats to each state.