I am assuming that Kijanki's entire post was intended as a joke, however for those who may take it seriously, the following:
Whether Copper oxide was ever used to make diodes does not support the notion that wires are diodes. The comparision is merely an example of faulty reasoning - "copper oxide can be used to make diodes, wires are made from copper, hence, wires are diodes." Socrates would love that one. The next time a diode goes out in a piece of electronic equipment, don't buy another diode, just grab a piece of glass (silicon) and tape it to the pcb. Diodes don't just magically appear because they are composed of an element that can also be used to make diodes. We are then in the realm of alchemy. The last bit of faulty reasoning I heard on this site as to new and exciting diode manufacturing techniques was that diodes were created by the extrusion process in manufacturing wire, I guess that theory was that the process created a taper and that resulted in a diode - kind of like a funnel I suppose - make up the science as you go along approach. Furthermore, what happens inside a wire is well defined, complicated or not, with regard to the effect the wire has on an electrical signal transduced to sound. Whatever deep quantum mysteries lurk within the realm of the eerie wire are of no significance when it comes to listening to the end result or in measuring the audio frequency signal at the ends of the wires. Surely the remark as to the speed of current flow within a wire was intended as a joke, and if not, even readers with no technical or scientific background will realize that this is an incorrect statement. One thing I have always wondered with the mysteries beyond the realm of science argument is how we are able to repeatedly make reliable complicated electronic equipment if there is so much to chance as a meaningful probability that a wire will act as a diode. Wires are not diodes, diodes are diodes, wires conduct equally well in either direction.