I recommend watching live feeding for inexperienced keepers.
However, I never sit and watch unless the snake has the rat in a poor position.
This is what I personally do:
This is on top of the other responsible live feeding methods that I practice, such as feeding the appropriate size feeder, keep the feeder well fed and watered, and do not leave feeder in with the snake for longer than 30 minutes.
The pictures you have seen are feeders that have been left with snakes for extended periods of time and have gone hungry. Hungry rats will eat whatever else is in the tub with them. AKA the snake.
These are irresponsible feeding incidents.
Some responsible live feeding tips: