I think it's totally fine for Amazon to sell lab-grade chemicals regardless of whether there's a common household use for them. I've personally bought chemicals like this for use in an aquarium.

It makes absolutely no sense to blame neutral 3rd parties in someone's suicide. If Amazon's "frequently bought together" feature suggested anti-vomiting agents and a book discussing suicide techniques, that's a pretty unfortunate and I'd really like to see a screenshot proof, but doesn't change the fact that person likely had acquired all the information they needed independently. These personal injury are grifters preying on grieving families.

Their claim that "Amazon is a serial killer" is one of the most ridiculous and hyperbolic things I've read in a while.