Why it's not a good idea to release exotic pets into a local ecosystem?

The reason is these "exotic" pets are most definitely not going to be a natural animal to the ecosystem that can result in a invasive species that can destroy the ecosystem killing multiple species and driving out natural fauna and flora.

It isn't a good idea to release exotic pet (a rare or usual pet) because if it carries an unknown disease, they can spread it to the human population. Therefore, it can cause many people to die.