Myth 14 Double negatives are illogical

One of the arguments as to why double negatives are illogical is math. Because in math double negatives cancel each other out. According to that logic not untrue should in fact mean true.
This system is in fact not the best argument to use, what about when a sentence has three negatives? ‘I didn’t give nothing to no one’, so two negatives cancel each other out, but one stays and which one is that?
Double negatives, or even more negatives, make a sentence sound more empathetic or make the denial/rejection clearer. Double negation is found in most languages in the world.

In verbal conversation I really don't mind double negatives, but it can be a bit confusing when you are not paying attention while reading. I do agree that in can put more emphasis on the message that is being send and as long as it keeps doing that I don't mind people using double negatives.