Slightly joking: but maybe "intelligence" is partly "empathy"? In my view, a truly evolved and highly intelligent species would be one that causes no harm, distress and certainly no pain or suffering to anything else.
So, to answer your question:
> If they're so smart why aren't I on their plate instead?
For the same reason I and grandparent commentor don't eat them: because we know their intelligence. If they were more intelligent that humans, that reasoning would mean they won't eat humans.
Slightly more on topic: humans often show a very narrow world view. In that many humans fail to see that there are other types of "intelligence" for example. We project our own narrow world-view onto others: "Intelligence means, you should eat anything that's less intelligent than you" (very much parafrasing, I know)
I like how its mainly just a pile of old fisherman tales with very little proven recorded attacks. The Cephalopods have been haunting our nightmares for over a thousand years.
