This dangerous myth that bull breeds, originally bred for fighting, were historically known as 'Nanny Dogs' has to be countered. It is unfair on inexperienced owners and unfair on the dogs, who may not be cared for properly/dumped.
The 'Nanny Dog' myth came from Colby, a US breeder of fighting dogs, seeking to broaden his market. His dogs killed his nephew, so weren't exactly nannying him: https://blog.dogsbite.org/2010/05/1909-fatality-john-p-colbys-fighting.html
The 'Nanny Dog' myth is perpetuated by Pitbull advocates in the US and is occasionally also seen in the UK, with Battersea among those promoting it for Staffordshire Bull Terriers: https://www.battersea.org.uk/pet-advice/dog-advice/finding-right-dog-you/staffies
There is now a social media campaign with owners seeking to 'show the soft side' of their XL Bullies. Some very inexperienced owners who got XL Bullies as their first dogs are speaking out on their dogs being 'misunderstood': https://www.dailymail.co.uk/femail/article-12519333/My-American-Bully-XL-look-scary-trust-nine-month-old-heartbroken-owners-defend-giant-breed-banned-UK-spate-vicious-dog-attacks.html
Bull breeds are fighting dogs, with the instincts and capabilities to fight, putting children, adults and other animals at risk. Retrievers retrieve, pointers point, herders herd. An animal charity would not have a campaign describing border collies as couch potatoes that can be left alone all day in a flat. So why are bull breeds pushed as 'Nanny Dogs'. There needs to be pressure on those (particularly organisations and media) repeating the 'Nanny Dog' myth to be honest about the origins and capabilities of these dogs, as well as the requirements and responsibilities of owning them.