I just believe the fundamental interpretation of the situation is forced upon the reader. Leading, if you will, to a "correct" answer.

Let me demonstrate with another phrase: "Blood is thicker than water."

Straight forward, right? Your family comes first. But this is a forced perspective. The original phrase means the opposite: "The blood of the covenant is thicker than the water of the womb."

Suddenly, it means that family isn't as important as the friends you've been through shit with.

I believe the same simplification is at work in the posted scenario by changing who is what in the metaphors.