My take on it is, that basically he feels that it's better not to wear any comfortable shoes. So they came to him and said there's these really comfortable year round slippers called crocs and he said it's assur. Any non-leather shoes that are comfortable would fall into the same category. I just read the article linked in the post before and I see them saying the same sevara. So maybe instead of all the news sites posting this article every year saying R' Elyashiv banned crocs on Yom Kippur, they should be more accurate and say R' Elyashiv banned all comfotable shoes on Yom Kippur!!!
Point is, there's no difference between crocs and what all the other (non croc) people are wearing!!