When you wrote " It isn't like I don't understand the basic physics and electrical engineering that supposedly governs what a cable can and can't do" I came to the conclusion you might be a physicist. You said Wilson puppies needed spade connectors and elsewhere you have described blowing up several of their tweeters, so I assumed these might be the speakers you were using.
I would like to believe you when you say the cables are directional. Usually this means cables are shielded and only one end of the shield is grounded, and this normally applies to interconnects. On Furutech's website there is a diagram which indicates the speaker cable is shielded, but there is no indication of whether the shield is grounded! There is the equivalent of a choke which removes some EMI. The main conductors seem very close together, so I suspect this is a high capacitance cable which rolls of some high frequencies.
By the way, I use spade connectors on my Quad electrostatics (ESL-2905) which are regarded as very accurate transducers and have amplifier-like specifications. In a rash moment I bought a secondhand cable set with banana connectors for my KEF Reference 1 speakers. I have not got around to bi-wiring or cable swapping because I am very happy with what I am hearing!
