This is a very interesting interpretation. Of course, I am sure that many who read the passage literally will disagree with Funk, but he is making an interesting argument well rooted in the period's customs, some of which, I was surprised t lear for the first time. By the way, using the left hand for "dirty tasks" is still the custom of desert dwellers, and at dinner, it is an offense to have the left hand out of your garment. Since most beduins dishes are eaten by hand and from common dishes, it is a very important lesson to learn.
MLK must have learned his approach to peacefull defiance and protest directly from that passage.
Zeev