No religion permits slaughter. Every politival party has indulged in some form of killings to protect thier turf - Congress in Delhi, BJP in gujarat and the Communists in Nandigram. Thus no political party person can in that logic belong to any religion.
Political parties have used our sentiments, whether of religon, languages or castes to get elected. If BJP uses Hinduism, Congress has fostered the reservations and indulged in minority appeasement for their own gains.
I believe that we must ignore the religion or caste sermons given by political parties and judge them on their positive work only.