Mumsnet... good one, mate
Cars aren't always blamed but they absolutely SHOULD be designed to minimise injuries to pedestrians and occupants. I don't get how you can argue otherwise. Police do seek to ensure the car was not speeding or the driver was not impaired, as they should, but don't automatically assign blame to the driver. In many accidents its a combination of pedestrian and driver error eg. jaywalking plus speeding.
You're arguing like all pedestrians are at fault for being knocked down or that there's a handful of people getting knocked down that are giving drivers a bad name. 500 odd people (25% children) a year are killed and 30,000 get injured in the UK - did they all get what they deserved? From reading your post, it's like no driver is ever at fault for a pedestrian death. That no one speeds through 30mph zones or gets distracted.
It's borderline sociopathic to not want your car design compromised in order to make it safer for other road users. Aesthetic changes to make a car safer will not affect how it operates. Blame is completely irrelevant - cars should be made to be as safe as they can possibly be for occupants and other road users.