I am equally surprised by the comments about how come engineers implement such systems, how they find it ethical, etc. I'm sorry, but it sounds just a bit out of touch with the real world, or just outside of HN bubble. Given the things that money motivates people to do, it's probably one of the least unethical things that has been done.
I am not judging that this is right or wrong, I am simply stating the fact that nothing about this should be surprising. Yes, this is slightly sad, but that's simply the reality of technological advancement. It's not really possible to expect the rest of the world to use the technology only for things considered 'right', etc.