Also, didn’t Ed Boon said they wanted to be over the top and cartoony. In can see why they use this stuff as references but I suppose what the studio is aspiring for verisimilitude rather than outright realism. I don’t think is necessary to see videos of cows getting slaughtered.
The thing is, for most creatives, aiming for authenticity almost always requires that you get as many reference materials as you can. Depending on the subject matter, this may necessitate that you go into things normally out of your comfort zone, whether it's graphic sex or porn (if you're a hentai/erotic artist

) or violent/gory Liveleak clips (if you're working on violent movies/entertainment media). I don't think NRS is mandating their artists to look at snuff clips; I think it's the artists themselves who soldier through it for the sake of authenticity and realism, especially in this day and age of ultra-realistic vidya game violence.