These are also good points. My first responsibility is to the 115 snakes in my current collection which is why I won't even walk into these stores any more. If I bring home a mite - and yes they do hitchhike - I have not done them or myself any favors. If I picked up one with a collection-killing virus or crypto then I've really abrogated my responsibility to keep them safe and healthy.
That's not to say that I don't take in rescues - I do - but they're because animal control called with a danger noodle they're not equipped to handle. While they're often abandoned or neglected, those snakes are typically in better condition than the ones for sale at the big box retail stores.