Because it's made of nylon, it needs to have its ends melted in order to keep from unravelling.
Step 1: History
The same properties which soldiers appreciate in paracord are also useful in civilian applications. After World War II parachute cord became available to civilians, first as military surplus and then as a common retail product from various surplus stores and websites. While some commercially available paracord is made to specification, even when labeled as such a given product may not correspond exactly to a specific military type and can be of differing construction, quality, color, or strength. Particularly poor quality examples may have significantly fewer strands in the sheath or core, cores constructed of bulk fiber rather than individual yarns, or include materials other than nylon.