Which is just stupid! Regardless, it is their fault for allowing her to have unsupervised access to it if she can't regulate the use appropriately, autistic or not. Instructions and warnings are there. If you choose to not read them, it's on you when something bad as warned would happen. It sucks, but that's the truth.

You let your kid, who even under the best neurotypical high intelligence cases is still a minor without a fully developed brain, do something they shouldn't, the guardian is at fault. If a toddler is left outside by a pool unsupervised, it's not the fault of the pool company when they fall in and drown; it's the parents'. If you let your kid have a bottle of tylenol and don't teach them the proper dosing and precautions and they accidentally OD, it's not Tylenol's fault, it's the parents'. It's unfortunate and it's unintentional, but it still falls on the parents when all the warnings and instructions are right there (or easily accessed). They could use this as a learning moment and spread that knowledge to more parents who are ignorant to it. Take a more active role, monitor your kids, teach them proper use of things, learn about the safety and safe use of things before handing them off to kids. Blaming the manufacturers doesn't solve anything.