Well yes, in fact the respect level can be taken to such an extreme that it becomes burdensome, which is the origin of the term White Elephant (there are religious reasons why white elephants are given more respect than others as well).
The treatment of elephants is for much the same reason there are sacred cows in Hinduism. While it is true that both can be eaten, there was a realization that they provide much more by being allowed to live and being put to work.
In other words, eat an elephant and you'll eat for, well a fortnight or so, put an elephant's strength to work and you can make life such that you can eat for as long as the fields still give yields and there are people looking for rides.