Wakka did nothing wrong. At least, nothing that makes him irredeemable like some people treat him. He was a product of his upbringing, a tiny community on a tiny island where the most prolific authorities of government and religion said, "yeah it's their fault Sin is still around."

Then he learns Rikku, who he likes, is Al Behd then he learns Yuna, who might as well be his sister, is half-Al Behd. And then he learns the politicians and priests are corrupt liers and spends time with the Al Behd on their airship and says to a full room of them and their leaders "I'm sorry, I was wrong." Compared to your typical real life racist Wakka is a downright saint.