Lawful Evil doesn't abide by societies laws, they abide by their own personal code of ethos, or perhaps abide by the laws of the villainous society they are a member of. For example, a devil would have no problem walking into waterdeep and murdering a nursery full of babies. However that devil would be unlikely to disobey a more powerful devil, whom ordered him to leave the babies alone, because that devil didn't believe in killing young prey.