“always remember that animals have nervous systems and can and do experience pain and suffering.”
pain and suffering is a function of consciousness not a nervous system. animals can make motions which appear to as as pain and suffering. perhaps it is, perhaps its not. you can program a robot (ala steven spielbergs creations) to appear to experience pain.
“Yom Kippur is approaching, a day when we may not wear leather shoes. This is because we must have mercy on animals if we expect Hashem to have mercy on us.”
that’s a nice thought but it has nothing to do with why we dont wear leather shoes.
its perfectly fine to wear a leather belt or hat or skirt on Yom Kippur. you can also wear a full mink coat if you like.