Right wing separated on landing. Left wing remained attached. Unequal lift vector (0% right, 100% left) induced roll. Lack of right wing meant no mechanical resistance to roll. Fuselage inverted.
Regulation isn't going to affect any of that.
Why the plane was landing hot at a high sink-rate (1200 fpm vs. ~600 max on stabilised approach), with no flaps, might have some grounding in regulation, or more likely, maintenance and operations standards, but uninformed speculation is highly premature and the focus on such points is utterly unjustified distraction.
Regulation isn't going to affect any of that.
Why the plane was landing hot at a high sink-rate (1200 fpm vs. ~600 max on stabilised approach), with no flaps, might have some grounding in regulation, or more likely, maintenance and operations standards, but uninformed speculation is highly premature and the focus on such points is utterly unjustified distraction.