It appears like he may have been put there because he was deemed “aggressive” by a previous owner. This is unfortunately common in some places— yes, if your toddler grapples up the hamster like a hawk’s talons, it’s going to bite! If you provide proper husbandry this shouldn’t be an issue with you, though
It may also be possible he had something but has since gotten over it, but I’d assume a vet would talk this over with you before sending him off, at least if it may be reoccurring.
Best of luck with your new friend!