Mind of someone who has worked in customer service for to long kicking it, please do not be mean to the bottom of the rung sales floor employees. Yes they should know better, I have heard bad advice from them about every type of pet out there, it is not good that they are spreading this wrong information. At the same time though, they are not the people who make the corporate decisions about where the pets come from, they likely do not even get a say in what brand of food the pets are fed. That wrong advice they are unfortunately spreading is probably something they heard from some customer who owns that type of pet so they assumed it must me correct, it is not information that the company is telling them to say.
Yes the corporations are in it to sell more product and make more money, but unless there is a pet store chain I am not familiar with that pays their floor staff on commission they get nothing out of selling you more products. They are just trying to do their job. Sorry if this came off at all rude it is just from years for working for big corporations and being yelled at by guests for things I have no control over.