It really bugs me that when i answer a question and then the asker challenges my reply?

that i cant defend my opinion! is there a way you can reply to their comments? i will always stand by my beliefs, however i am also open to change but how can we defend our challengers on here, ? i fully accept that people will disagree with me at times, hence the thumbs down and vice-versa with the thumbs up, but it just riles me that you cant reply to the asker when they are asking you why you had that opinion or generally slating your answer! any thoughts will be greatly appreciated...and will not challenge your replies as i know you will be unhappy that you cant answer baack!