I liked the part where you posted the manga page and didn't read the thing properly. That was the best part for sure.
Anyway, to avoid writing a useless reply, I will say this: 8-tails said that he shouldn't, not couldn't. BIG difference.
It's because of the fact that the fox drains his chakra whilst in shadow clone mode (and no, it's not a new clone technique that he did in the last chapter) so the more shadow clones he uses, the more likely he is to die. However, Naruto is an Uzumaki => huge chakra amounts + starting to get the fox's respect => Naruto will be fine.
This ^, or just Kishi forgot about the shadow clone statement. I tend to go with the first one though.