Lookout Waterworks... "When in doubt, do without"... LOL. From scripture we can tell that all our words are either being kept for future judgment or being deducted from heavenly reward as we go through life. To put it bluntly, I would suggest you never curse anyone and immediately repent when you do (assuming you're a sinner like me). Once we have the poison in our heads and a natural temper to go with it, it's common to explode sometimes (especially if you hit your thumb with a hammer. I say there are no biblical contradictions, just lack of penetration. You have two root powers to help you answer all things, Conscience and Holy Spirit. Use these and expect to take your medicine at the end; For none of us are clean but all forgiven if we remain repentant of heart. And seeing that none know the heart, then we must all just "go with the flow" of our own judgments concerning all matters and rest on God's mercy in the end.

Don't be decieved by any flesh pretending to be clean and telling you this and that, work it out inside yourself as I said, trusting God to understand your weakness in all cases.

Now, you've got to do a bunch of thinking about all the rules, and it is so important, because we are Princes and "Practicing Gods" here. Your seemingly simple and innocent question has much more depth than first supposed, because the lesson concerns "all words" we may utter in the course of our lives and this is no small matter overall.

I say, if 'A' rises up in righteous indignation and calls 'B' a fool by the spirit, then 'B' is indeed a fool for the spirit knows the heart of 'B' and speaks the truth! But such spoken lacking that same spirit is the folly! (I think this should explain what you have found in the scriptures).

Furthermore, many biblical things like this are purposely left loose to test our keenness of discernment concerning our judgments as Princes and future Gods, for we are in school, have the Book for study, and will recieve a grade make no mistake about that!