Heh,
Because the so called exotics have so far been seen to, and indeed can only, do less damage to the indigenous wildlife than has already been done by the so called domesticated pets.
Compared to the problems caused by cats, dogs and well meaning "fish for food" species being introduced into the various ecosystems around the world the pythons in florida are a fart in a thimble.
They also, at this current point, have a far greater potential to be used as a gene bank to repopulate the wild in the case of ecological disaster than any other class of pet.
dr del