I can totally get where you're coming from. Did he ever tell you why he no longer wanted your friendship? It sounds a bit harsh, especially if he didn't give you an explanation.

I understand why your friend is bringing him up in conversation if they're still good buddies. I bet it's unintentional and is just caught up in a story.. and maybe because he's a "taboo" conversation, subconsciously, he may feel compelled to bring him up anyway. Or maybe he just doesn't understand the hype since this guy wasn't your ex who (say) abused you in some way.

Is there a way to get closure to this ex friend? Did you have feelings for him beyond friendship?

Your current friend needs to be a little more sensitive to your feelings since it really bothers you that much.. or he runs the risk of you avoiding contact with him because of this guy.

I think you also need to do some healing so you don't run the risk of losing this friend, either.