electrical short 1 channel. Cable spade at fault?

Good advice from Onemug, if it's the amp your best hope is that there is a fuse in the circuit that protected the amp.

I had an Audio Refinement Complete integrated, the predecessor of the YBA 201, I think, and blew out the right channel when a pair of speakers arrived with an internal short. There was no fuse in the circuit and the cost to replace all the blown resistors was just about exactly the value of the amp, ~$500. I paid it rather than throw the amp away but it wasn't fun.

Yes, I tried all the permutations including another amp and it is the YBA R channel.
Sfar,that is exactly what I feared about repair cost vs price paid.

Can I hold the cable seller liable for the tab?

No, you can't.

In the long run, if you want to use these cables, the problem has to be addressed. I have on a few occasions taken cables to my garage and fired up my grinder and filed down ends. Then change to a buffing pad and smoothed out the filing.. Always good results. I can see you not wanting to do this, but I am very handy, built a few things from scratch, modded a few products and built a few cables. This is not an outrageous project. I have also cut off ends and replaced them many times also... Spades to Banana's etc... also, a fairly simple project... Litz is not fun to work with....

Thank you all for your good advice.
I can return the cables.
The real cost is repairing the amp.
I do consider the product defective, and I do hold the seller responsible.