Use whatever terms you prefer: abortion - gun control, abortion policies - gun violence policies, abortion - gun violence. Given that both issues involve prudential choices in implementing policies to address the societal problems they pose, they are to that extent political and outside the purview of the church. That said, abortion, unlike gun/control/violence/policies, involves moral choices as well, and as such is a rightful and proper area for the involvement of the church, and by extension the clergy.
Abortion is a special case, and the reason ought to be obvious: it involves the destruction of a human life. If that is not sufficient reason it is hard to imagine what would qualify.