It depends. We're smarter than them, but that doesn't make us objectively better. I think you have to strike the right balance between seeing humans as the center of the universe and seeing humans as the scum of the Earth and source of all things bad (in other words, I think it's unfounded and unscientific to believe nature would be perfectly harmonious and peaceful if not for humans).
You're right that us being smarter doesn't give us dominion over other animals. I think it's probably wrong to kill pigs (as an example) for meat, even if we treated them humanely. Saying you eat pork because you like the taste and damn the consequences sounds very selfish, and is ethically indefensible.
However, I don't see the harm in eating things like oysters or crawdads or lobsters. In my view mammals and birds and some fish are intelligent enough for us to consider their interests and desires, but the intelligence of insects and crustaceans and mollusks (excluding cephalopods) is so minimal that there is no merit to treating them as if they were as smart as a dog or pig.