« The social function it serves » rather than « the reason » would have been a better wording. The rest is only narrative interpretation. Which in the end is what everyone does with these old texts.
Discussion
There is significant room for interpretation, to be sure. However, the text itself does provide limits for the scope of that interpretation, assuming those who believe it to be worth basing their faith on it are unwilling to contradict it explicitly.
Thus, even though every theological tradition disagrees about exactly what way the bread and the wine are Jesus' body and blood, none of them say the bread and wine in no way represent Jesus' body and blood whatsoever, and they all recognize it relates to Christ's atoning work on the cross. They all readily recognize the limitation the text itself places upon them, and then disagree about exactly how that works itself out in the details.
Once we go outside of that scope of agreement all Christian traditions share, it is very likely we simply aren't believing what the text says, rather than merely disagreeing with how it ought to be interpreted.