rabbits can't kill each other with one bite.
People have posted on this very forum about accidents that have happened and one animal has got access to an area they shouldn't have and one of the animals has ended up dead. Accidents happen, no matter how careful you THINK you are going to be.
I wouldn't keep any predator / prey species in a house together if either of them were allowed loose. So if I had a dog I wouldn't keep any species that it could kill.
I agree to a certain extent - but I think it's more of a measured risk. When I had Border Colin for that short time, he wasn't allowed access to my back garden - even though the buns were in an aviary - but that was because I didn't know how he would react or how my buns would feel even just seeing him.
I would never leave a dog & bun alone together, no matter how well I knew dog & bun - same goes for dog & young child though.
Accidents do happen - even when they shouldn't, but if you are taking all the precautions then I think it's a careful risk