Why should caste & religious sentiments not to be allowed to play an important role in elections in a democracy?

The following points may help you:

a. Caste system has been well entrenched in Indian society from time immemorial and has brought about worst kind discrimination and exclusion of the out caste group who were subjected to inhuman treatment and injustice. 

b. Caste has also emerged as major vote bank factor during elections. Political parties try to muster support on the basis of caste by exploiting the caste sentiments of the people, fielding candidates of a particular caste to reach out to more and more people.

c. Likewise, political parties also make use of religion and exploit it as a political factor.

d. They use  religious symbols, values to incite the masses against a particular religious community.

e. This certainly becomes a source of conflict in the society.

f. It pits one groups against another.

g. It hampers the stability and peace in the society, and may in the long run may lead to disintegration of the country.

h. Elections must be fair, , free and impartial where people must chose on the basis of party ideology , candidates past record and performance.

j. Exploiting factors like caste, religion only leads to chaos, tensions and breaks the unity of the country.