How is communalism a hindrance in the functioning of our democracy?

In a democracy, the political parties compete against each other, and most of the times this competition gives rise to hastiness among the parties.

a. The competition against each other divides society.

b. Many times these parties support any one community to gain their vote, while this leads to communalism between the communities.

c. Sometimes the people of a specific community caste their vote to the candidate of their own community even without knowing his identity.

d. Communities raise demands which are against the constitutional means and sometimes their demands are at the cost of other communities.