Three are actually some good reasons for providing a real ID and paper trail for hazmat truck drivers. Hamat disposal has often been simply _discarded_, dumped in open sewer drains or in inappropriate landfill, or dumped out at sea. The results have included medical refuse washing up on beaches and mercury in water supplies. Other hazmat materials have crashed and _leaked_ in residential areas where they were legally forbidden from travel. A basic ID and criminal check for handling such materials may exist for anti-terrorism reasons, but it has sensible use to prevent truck drivers who've been convicted of mishandling hazardous material in one state from being re-employed in another state.
Because of the money involved, and the opportunity to increase profits by cutting corners, hazmat _needs_ to be carefully regulated. Even if it's promoted for "security theater" reasons, it's a field where safety and verifying the source and delivery of material is important to commerce and safety.