I see now you were right and I was wrong.
You were quite right to query this assertion - it is indeed incorrect.
They were wrong / It was wrong of them to dismiss him. / They should not have dismissed him.
Challenging his position was the wrong thing to do, even though it seemed the right thing at the time.
You are correct // wrong in your assumption that...
lub
Your assumption that... is correct // wrong.
To say this is flying in the face of the facts / is contrary to the facts as we know them.