I have found that it is best to address subjects in general rather than specifically addressing those with whom you have the disagreement. If you have a disagreement with someone then address the subject rather than mentioning the person by name. Granted, sometimes a specific quotation is necessary, but most of the time you can deal with the issue without ever bringing up the name of the person you have the disagreement with. This, I believe, greatly encourages change in the mind of the person you disagree with. If you truly have the truth, and this person comes across your writings seeing that you are sticking with the general issue rather than trying to name names, impute motives, etc. they are more apt to see their error if they are in fact in error.
Father, help us all do unto others as we would have them do unto us. This is the law and the prophets. (Matthew 7:12)
EMJ