That's not true. Snakeheads are good eatting and in Asia they have medical use. It's said that snakehead soup helps you after surgery. They say the some people let them go with the idea they could catch them and sell them here in the USA. So they did not have to deal with importing them. It really had nothing to do with fish keepers.
If anyone watched the show (gigas12) even Florida Fish and Game said that it was not hobbyists, it was people that thought they could profit from the species being in the USA, for medicinal purposes (for example areas that have a large Asian population). No offense to anyone.
the containment of trying to breed anything would have to have a major control factor so i dont think reckless releasing for profits is to blame. Mystical asian beliefs of releasing fish for rituals would make more sense