Arguments that animals aren't stupid usually involve chimps poking sticks into holes to eat termites. We are clearly superior to animals, regardless of how fast they can fly, or how much weight they can lift as a proportion of their body weight, or how long they can stay underwater without coming up to breathe.
It is easy to mix up the human mind with technology. Technology is an offspring of the human mind, but not a trait of it. Physically, humans haven't changed much the last 1000s of years or so. The ancestors of those people sending probes into space were people who thought thunder was coming from a specific god. Yet physically, they were largely the same. The most important differences should be the upbringing - the education.

Furthermore, if creatures such as dolphins were as smart as human beings, they would have a hard time manifesting it in a way that we could gauge it.

We can a make a choice which animals cannot, and given that our rejection of irrational, mechanistic behaviour is what distinguishes us from animals, the rejection of killing for pleasure is a necessary step we must take in order to further separate that divide and increase the prestige of our achievements as human beings. To reject it is to embrace civilisation.
We aren't all that terribly distinct from the other animals, really. It does not make sense to differ from other animals for the sake of it, either.