But even with that as a ‘standard’ they cannot agree.
The whole idea of individuals being able to interpret Scripture is ludicrous based upon that alone, never mind that the Bible tells them that it is verboten. More evidence that our Bible-only friends are full of man-made traditions and, intentionally bereft of Christ’s institution upon Earth, cannot make the correct decisions, the correct interpretations or the correct doctrines.
Yup, see 2,626. That's all they have, so they use the Bible to provie the Bible, but it all defaults to "I believe this is so..." (personal opinion based on personal interpretation) and "God told me," (gnosticism) and, my favorrite, "I don't trust any man (read: except myself)." It's the ultimate narcissism.