The article isn't using the correct terminologies when describing the surgery. These woman don't just get double jaw surgery, they also get their jaw sawed and reshaped into a V shaped, hence why the scarring tactics written there. Obviously, double jaw surgery is invasive and does come with serious potential risks, but they make it seem that all bad cases that come from there are from the regular jaw surgery, which is not the case.
Also, reason complication rates are high there is mainly because the competition in the field is ridiculously high which means some the clinics offering these procedures tend to use interns/students to operate on their patients, it's not even the head doctor who's doing the work. Scary stuff.