Of course not. This is just a clarification about another point of law that a typical drug dealer violates, which gives law enforcement yet another angle.

In some cases proving tax evasion is easier than proving other crimes. This is what got Al Capone -- because the crime was perpetrated through his organization and not by him directly, it would have been difficult to hold him directly responsible for the crimes. However, once his ledger was discovered it was straightforward to prove that he received significant income without making the required income tax payments.