Never in your original post did you say that these things 'sometimes' happen. It really looked like you thinking it was a very big thing. And like the others said, you can't talk bad about something you never tried. I'd understand not wanting to risk it but then you can't go off and say it's an immoral thing to do.
With proper knowledge and supervision feeding live is safe. Like those people who has fed thousands of snakes live prey and not one injury because they are cautious.