It's more of a total picture thing. If the final product, the thing the purchaser is putting out money for, is covered in urine and feces when they're sold, how do you suppose they were kept prior to that?
I few poops or spots of urine are not out of line, just using a CO2 chamber will leave that behind, but it won't coat hair or cause the animals to stink when thawed. They should be nice and clean.
They lied about it on fauna, then denied it when they were caught and finally admitted to it but passed the buck to their suppliers at least one of which had his entire facility, cages and animals burnt to the ground by the CDC because this Virus the rodents had was NOT killed by freezing and could kill humans. It made several people very sick.
Some of their suppliers may be good, but some of them are beneath the bottom of the pile selling pure crap to the unsuspecting.