It's like having a massive open fireplace in your living room and if a toddling baby falls in you say "it was just an accident, surely losing your baby is enough punishment?"
I don't really understand this - that is what happens - I've never heard of somebody going to prison for their baby having an avoidable accident at home? It's different if the parents were passed out from alcohol/drugs and the baby fell down the stairs or something.
The risks of dogs and small children are really poorly understood by a lot of people, I think it's quite likely to end up in a situation where parents literally didn't know they were taking a risk. And to find out in the most awful way :(
Maybe there should be more education in general rather than extremes (banning dogs, making blanket statements). Because it seems every time this happens the papers are outraged and then it gets into an unhelpfully "sided debate" where you have "dogs are evil menaces" vs "no they are innocent lovely creatures, my dog would never" and nothing changes. The reality is it's not about whether dogs are trustworthy or not, it's down to owners to take responsibility and accept their dog is capable of causing harm and manage that risk.
Dog licensing with a mandatory course about dog psychology, modern training methods and the risks around young children/other animals would be the best approach IMO. Phase it in so that existing dog owners have chance to get the qualification. Since all dogs have to be microchipped and registered it would be easy to prove you were already a dog owner by a certain date and do a shorter course. Maybe refresher courses if someone is responsible for an anti-social dog incident (minor bite etc)? Like those speed awareness things. Everybody accepts that cars are risky but beneficial, so we manage the risks. There doesn't need to be a debate between "All cars are killing machines, ban them" vs "But I am a perfectly safe driver!" - it's simple - we make people pass a test to get a licence and then they are banned if they can't handle the risk reliably.