Long after Christ publicly uttered the words "it is finished" from the cross Paul wrote that Christians should "proclaim Christ crucified" (I Cor 1) and Paul emphasized that he knew "nothing while I was with you except Jesus Christ, and him crucified" (I Cor 2)
You have not and cannot explained this biblical fact away - a biblical fact that is at odds with your distaste for the including the corpus on the cross.
Long before Christ was crucified, God gave the law to Moses saying "Thou shalt not make unto thee any graven image." Because many people pray to the crucifix and other statuary, it is best that it not be used.