The purpose of the universe is to create beings that know and create. It is the nature of intelligence to create intelligence.
I think the main problem is that humans are extremely conceited and think they are the center of the universe.
It used to be heresy to consider that the earth revolves around the Sun. And I'm sure after it was proven that it does, many thought the Sun was the center of the universe, or at least the Milky Way.
If humans have so little respect for what is around them, they will die out.
Who is to say what is intelligent and what is not? If you don't respect nature, it sure will not respect you.