The substances may overlap in some areas, but the defining goal of two groups are often directly contradictory. The goal of a group whose primary goal is to criminalize abortion is directly contradictory to a group that wants to make or keep abortion legal. The fact that they may both support contraceptives is missing the forest for the trees, the primary goals of the two groups are indeed directly contradictory. Achieving the goal of one necessarily means the other fails in their goal. There's nothing artificial about this.