Legal or illegal, it is dangerous as heck.
Do you know about proper mixing? Corning? Making the correct fineness for your particular shooting iron?
The stuff we get comes from "professionals", who ARE using correct methods of mixing, corning, milling. Yet every few years, we hear of a black powder manufacturer having fires or explosions.
Fortunately these days, using "modern" methods, these do not usually lead to loss of life. Please do not risk YOUR life, or your home, or your family, in an attempt to manufacture "home-made" black powder. Go play frisbee on the interstate or something instead.
Won't be long before other BP makers take up the slack generated by Hodgen. Be patient.