Not silly at all
You just haven't seen as many pictures as I have.
The cuts are PRECISE and only the organs are taken. There is a case of one of the cows' heart being removed with only a one inch incision. The eyes and rectum are often cored out. The flesh looks seared around it's smooth edges, like it has been cut with a laser. I'm sure there are photos available on the web for this.
Although many theories abound, this is good summary of the possibilities from which it <stems.>