Say there's a bad law, for instance a law requiring that every toddler must be taken to a police station before the age of 3 to have one eye gouged out with a red hot steel bar.
Suddenly, the government decide to apply this law capriciously, and starts exempting left-handed boys from the eye gouging.
Would you complain that it's unfair that left-handed boys don't have their eyes gouged out? Would you say that two eyed people grow up to have an unfair advantage in the work place by being able to be more productive and earn more? Would that "fairness" be your concern? Would you feel better if the government reverted its policy and decided to apply the policy uniformly and resumed gouging the eyes of left-handed boy toddlers:
No! You would just want to make sure no one gets their eyes gouged out! Well there you go, focus your concern on the victims of the law, not on the lucky ones who manage to escape it.
That seems like a pretty poor example when no one would argue that it's morally wrong to require that some professions require licenses to operate (would you support an Uber for medical care as well?).
I think your point is that some amount of unconditional respect for the law is desirable, because it works as an enforcement mechanism. Is that right? Even if it is desirable, it does not mean that there is a duty to obey unjust laws. After all, saving children from starvation is desirable, yet most people consider they have no duty to do so.
Besides, I think that societies overwhelmingly err far on the side of too much respect for the law. Most people are content to form their opinions based on the status quo, which can make for some terrifying dystopian results.