copper corrodes a lot faster than aluminum so it was the copper plating that gave you your problem. I've bought brand new OFC from JL and it was green when I took it out of the package. if you dont want wire to corrode, get tinned copper.
the fuses protect against overloading the wire. in a comparison like this, they put more current than the CCA is rated for but the OFC can handle it. it would be like saying 8awg is crap because it cant handle 200amps but 0awg can handle it, so everyone should only use 0awg.