The Florida Supreme Court said, pertinently, referring to its own precedent, "We thus have recognized that generally 't is within the power of the Legislature to declare an act a crime regardless of the intent or knowledge of the violation thereof.' Coleman v. State ex rel. Jackson, 193 So. 84, 86 (Fla. 1939)."
You DO have to know you possess a substance, but the State does not have to prove that you KNEW it was an "illicit" substance (i.e., a controlled substance). However, a defendant can assume a burden (an affirmative defense) and try to show that although he knew he possessed the material, he did NOT know it was an illicit (i.e., controlled) substance.
The Florida Court went ON to cite SCOTUS decisions along the very same lines.
So why is anybody "seething?"
I don't like it, either. But there are legitimate ways of correcting it.