From a comment on someone else's post:
Views on the other issues you specifically called out ["The pro-life, the pro-choice, the Christian coalition, and the gun owners."] mostly tell us what a candidate thinks about religion and science. RKBA tell us what they think about *us*, and that's why a candidate's position on gun ownership is important beyond the guns themselves.
EDIT: Right to Keep and Bear Arms
Definition added on the off chance someone reading this doesn't know what it means.