They should recruit people on Reddit for this. A large number of them seem perfectly fine with this type of content. There are dedicated communities to all these things. I do not mean this as a hit against Reddit users. It is just that there are small pockets of people who are psychologically capable of tolerating this or even enjoy it. It seems more ethical to hire people from /r/watchpeopledie.
Perhaps. I would argue that there is some difference between seeing someone fall off a cliff and watching someone being tortured to death.
Edit: and saying things like "well clearly these people are already traumatized if they're seeking this out, it's not good for them, we shouldn't give these jobs to them" seems laughably paternalistic when the alternative is to traumatize more people by making them look at it instead.