They both involve raising animals for the purpose of killing them.
They do, although from what I've read most of the cow leather used for clothing comes from cows raised for food. Granted, almost any other type of leather, especially the better stuff (including cow), is probably specially bred. However, I doubt that they skin the calfs, deer, frogs, etc. and just throw away the rest. I was once asked (politely) by a girl who was into animal rights about a cheap vintage leather jacket I was wearing. I replied that I wasn't even alive when it was made, and by wearing it instead of buying a new one I might be saving a currently-alive cow. I also pointed out her leather shoes and purse, and she changed the subject.
If you're anti-fur, I say you should be wearing your feet wrapped in rubber and cloth (not wearing leather Birkenstocks or croc spike heels).
Many people who are, do. The Converse All-Star is one of the top shoes for the anti-fur set. I don't know how they feel about the Chinese labor conditions involved in making them, though.