Exchange of thoughts, ideas and learning, throwing and answering questions are exercises of the mind and the soul - you may call it debate, you may call it whatever you wish. If it is a sin to commit something which is not of its nature then it is also an error and sin not to use the mind and reason in time of need. Shutting off reason, ignoring inquiry and questions are blasphemous to the One who endowed man of it for his benefits.
Reason and proper use of it saves the man from fanaticism. Remember that religion and religious dogma made many people addicts/fanatics because they often shut off reason and exchange of ideas. Fanatics believe they have the absolute truth.
So when you come to my wall remember I did not invite you, you come by yourself. When you read I allow you to comment but I dissuade you from reprimanding me or those who are exchanging thoughts.