I know better, after all these years I should know not to let myself get provoked into responding to someone even denser than I am or whose beliefs are simply heretical. They are, like the demons of the Gadarene demoniac, legion. It really is, on my part, a sin because it usually boils down to someone stepping on my toes, trying to correct me on something I actually do know something about, in short my evil, egotistical pride is hurt. Christians are not supposed to let themselves be offended if slighted or insulted. Jesus told us to, "...turn the other cheek." Even is someone says we're of the devil or deliberately missinterprets what we've said we shouldn't respond. If I could say it and mean it, the best reply would be, "I love you and so does Jesus. God bless you." That however would be a lie because I couldn't in all honesty say, "I love you." There are any number of things I could say that would be honest but would not demonstrate love.
However I can do something that is Christian and will do them no harm and me a lot of good. Forgive them and repent of my pride and ask Jesus to forgive me. There are things that people can say that warrant a rebuke but ruffling my feathers or stepping on my toes is not one of them. Letting ourselves be offended is natural but it is not wise. When I say offended I mean allowing someone to provoke us to anger. Paul wrote, "Be angry and sin not." However, for myself, I've found it difficult to be angry and not sin, almost always with words. So, I try to guard myself against reacting to a slight or insult and ignore the ignoramus.