I dunno anything about “specific genetic resistance.” Usually I just hear people attribute it to his species’ insane Survivability relative to even other Dragon Ball characters. Like how Goku and Vegeta can barely take a single charge from Broly, but Frieza (who while stronger than them, is no where NEAR Broly in scope), can take that beating for an hour. Or how Frieza can take blows that vastly exceed his level of power from SSJ Goku, despite being stomped by him in physicals every time they clash. Even then, though, Namek exploding on Frieza, in the midst of Frieza’s condition, takes it to the utmost extreme and often people just shrug their shoulders at it.