Amazon is still facilitating it. If you’re selling guns to someone you know is a a serial killer, “someone else would have sold them a gun” is not a defense.
Edit: especially if you run ads about how effective your guns are for serial killing.
There’s a big difference between committing a crime and engaging in lawful commerce.
By your standard, HN is on the same level as Amazon, as there have been many articles here over the years describing technical details on how to implement such a system available to anyone. A serial killer may be using a raspberry pi based facial recognition system that he learned about here, right now to stalk a victim.
Implementation requires specialized skills for the hardware, software, and logistics, as well as lots of time, money, and patience. A stalker isn't going to deploy many pi zeros with cameras in many places on his own, and I'm not concerned that they will be able to round up many assistants.
Amazon's product takes care of all that nitty-gritty, thanks to the work of their many bright employees.
If a stalker isn't going to deploy many pi zeros with cameras, then Amazon isn't useful to him either. It's still up to the customer to actually take the images.
For implementing facial recognition, yeah, it takes a little bit of coding skill. Same as integrating with Rekognition.
Edit: especially if you run ads about how effective your guns are for serial killing.