Sentence:  But your father didn't exactly do wrong things: he said them and thought them: that was what was so dreadful. He really had a sort of religion of <WSD>wrongness</WSD>. Just as one doesn't mind men practising immorality so long as they own that they are in the wrong by preaching morality; so I couldn't forgive Andrew for preaching immorality while he practised morality. 
Meaning of the word marked with <WSD> tags:  Wrong or reprehensible things or actions.