Give me a concrete example of something that humans can do that no other animal can do and why that ability, and that ability alone, merits the word 'sentience', or if you like 'true sentience'.
You're mixing your terms up badly here, btw. Do you mean 'intelligence' or 'sentience'? I think you first need to define your terms.
I disagree with JeffR about quite a bit, but on this particular point we're in broad agreement. The reason it's ok to exploit other animals, if it is ok, is not because they're not sentient in our special way.
Seriously? you're using the internet to ask me for an example of something humans can do and no other animal can do?
OK let's start look out the window and you see the products of human science and technology all of which trace back to human intelligence. Science didn't make us smart, being smart gave us science.
And whilst it may seem counter-intuitive it gave us religion since no other creature wonders what the universe is for.
We can build a fire, Chimps who have been around longer than us and have the same flexible hands can't do that. And fire started us on the road that led to where we are now, iron was initially made by chucking lumps of hametite into a fire letting the carbon and oxygen burn off and the iron clumped at the bottom. This required not only the ability to build a fire but the ability to consider that burning rocks might be a productive idea so we can visualise abstract possibilities.
We can store information, we've always done that be it digitally, on paper, stone tablet or painting it on cave walls. We can send messages and information to individuals not present. Other animals can communicate to individuals present but leaving long term information is beyond anyone bar us.
We mark the passage of time not just tell the difference between night and day. before we had calendars and clocks we moved stones about.
We can manipulate other species across multiple generations dogs and chickens and a host of other species exist because we selectively bred them.
We can talk other animals cannot, they can communicate simple things of course like "Danger" or "Food Here" but we can communicate abstract concepts (another thing which only we can do)
Some animals can also grasp in a limited way human concepts such as a name. A Dog don't understand the concept of name as something that distinguishes them from other dogs but it can understand that the human uses that sound to summon them.
OK Sapience is probably a better word than sentience for what I'm trying to put across but yes there is a clear gulf between us and everything else.
As for exploiting other animals because we are smarter than them well we've been doing that since we first started putting up fences, we wouldn't exploit anything if we weren't smarter than it we'd be too busy dodging the apex predators of which without our brains we wouldn't be one of.