No, the medical community does not classify sex without contraceptives as NFP.  Blaming the person ("lack of self-control") is the typical accusation made toward people whose bodies are not robotic machines that work in the perfect way that NFP requires. The statistics given are always for perfect use (that is the technical term, not "appropriately measured").  Failure rate for typical use is higher, which comes from errors or a system that is irregular for all sorts of reasons - virus, stress, increased exercise, PCOS, age, and many more.  Current ob-gyn statistics indicate that 30% of women experience irregular menses during their reproductive years where NFP is difficult to apply , if not impossible because signals are unclear . For those for whom it works, it's natural and healthier but only if the woman's body is on a fairly regular cycle. But there are many for whom it does not work, and they are not helped by your judgmental attitude.