Not at all.
The law is written such that the clerk must know that it is being used for illegal purposes. That's why the undercover guys are telling them.
The whole point of the article is that these immigrant clerks "don't understand" English or the slang being used; therefore, they should not be prosecuted for selling 50 boxes (or whatever) of Sudafed to one person.
Too bad. Learn to speaka da English.
Your offensive stereotype is also missing the point. My family came here circa 1640, but I have no idea what "a cook" is, other than something to do with the kitchen.