Not really seeing why this should be illegal.
See, for example, emerald ash borers.
* Spreading diseases
* Introducing an invasive species to a vulnerable environment
* Encouraging expanded trade in endangered species (gets more people interested, which causes them to go extinct faster)
Not to mention the fraud he committed in order to import in the first place.
Look at what kudzu is doing to the South or invasive Asian carp are doing to midwest waterways to get a sense of why that is an absolutely batshit insane thing to do and why it should be massively illegal. Invasive species are like biological weapons of massive destruction. Their potential blast radius is damn near infinite.