A centurion is a Roman officer with 100 armed soldiers at his command.
It doesn't require much biblical insight to understand why Jesus didn't dare to call such a person a dog to his face.
But Jesus never relented from his teaching that gentiles are dogs - subhuman.
As for the apostles who "had visions of angels" contradicting the instructions of Jesus, and preached to the subhuman goyim and made a lot of money, I think Jesus the racist was a more honest man than any of them.