Is it really that odd? When every time someone tries to sell you a snake they tell you it's pooing properly?

How did you treat the similar symptoms you mentioned in young corn snakes?

You would think after all the screening done, samples taken and one of my snakes euthanized and put under the knife that anything bacterial would show up!? Also, although some bacteria strains are stubborn to treatment, you would expect some resolve through all the past treatments/medication action taken. I wouldn't like to push more than seven courses of antibiotics for 40 snakes and would expect that to knock the back out of any diagnosis!
Which makes me also speculate!, that it could be viral and got into the gut?