Vince Gilligan wasn't writing about the socio-cultural impact of meth, or the physical effects of Meth addiction. He was writing about a middle class white guy struggling to make it, and the lengths that he would go to to make it, and what a slippery slope that is. Far more in his wheelhouse.
He's not writing about Medieval history, he's writing fantasy. I think if there were medieval individuals roaming the streets they might take issue with his deformation of their experience -- or maybe not, since Game doesn't trade on 'historical authenticity'. And because 'medieval white people' are not an oppressed minority, struggling to gain respect, acceptance, and equality in the modern era.George R.R. Martin did not experience one part of medieval history yet that still influences Game of Thrones.
The only example even remotely relevant here is Wonder Woman and Grant Morrison, and Grant Morrison did extensive research into feminist theory and literature before he tackled that character. If he ends up writing a book that he's marketed and stated was about women but which is obviously and explicitly about men then, yeah, I think he'll be very open to criticism.Ed Brubaker knows nothing about being a spy yet is writing Velvet. Brian K. Vaughan knows nothing about being a female so should he not have written Y: The Last Man? Should Grant Morrison not write Wonder Woman because he lacks a vagina? What about Joss Whedon and his extensive popularity for writing good female characters? Is that problematic?