I have a background in animal rescue. I do believe that anyone who breeds animals should be thinking about the home the animal will receive, particularly if they may require special care. I have seen far too many breeders sell large breed puppies to owners living in an apartment, with no dog owning experience, and those situations end very badly. And the breeders could care less because it is NOT their problem. A giant snake that will require 2 grown men to lift it, and will require a LOT of space, well they have special needs that should be considered too.
For me it is about the animal, first and foremost. Perhaps this was NOT an impulse buy? Perhaps the person that sold the snake had a long discussion with the purchaser regarding how this snake differs from a rainbow boa and what they should expect 10 years from now? Maybe the OP will explain. I maybe assuming to much, clarification will help. But the original post did not imply that the seller went into detail.