The absence of intelligence is non-intelligence, which isn't the same as stupidity.
A rock isn't intelligent, but it's not stupid. It's merely non-intelligent. The universe is full of non-intelligent matter. There is only a little big of intelligent matter that we can see, starting in the animal kingdom and reaching its pinnacle in man.
We may live to see true Artificial Intelligence, which would be interesting.
Do you believe that human conscience and consciousness ultimately came from mindlessness?