Sort of like how an SS officer at Auschwitz knew about scheduling trains.
The SS officer brought misery and death. The drug dealer brings misery and death. To brag about either "profession" is repulsive, and tells you much about the person doing the bragging.
... but we need to legalize it according to some...
Exactly how I feel about all the fools who defended their enjoyment of "Breaking Bad." All I ever heard was "he was forced into it, he did it for his family." When all along, "he" is literally selling death, as if any sane, normal person would choose to do such a thing for his family.
And then what happens in the final show? He admits it - he did it, not for his family, but for the enjoyment of it. Because, in other words, he was a sociopath. And in doing so, the show made fools of all of its fans, yet no one realizes it yet.