Guns aren’t totally banned in the UK, but are capability restricted and their (legitimate) supply restricted.
BB gun with low power and generally low harm. Little restriction.
AK47 with high power and capability to do serious harm - banned.
In theory I could have that AK in my house, mounted on my wall or even locked away and it wouldn’t cause any harm, BUT if I have a moment of anger or a mental health emergency and the capability to do serious harm is apparent.
Chemicals, explosives, vehicles, we have restrictions on all these things.
The 6ft-lb rule on airguns in the UK and a lot of Europe always seemed ridiculous to me, especially since a lot of the 25~35ft-lb air rifles were made there! There is a lot of need for things like that in more rural parts of the UK which seems to be possible with some licensing but, that is largely an academic exercise for me to research the specifics on.
In terms of serious harm, military firearms have a huge potential for damage just like cars. In terms of a "moment of anger" or "mental health emergency", those almost never happen in isolation. To be honest, I don't want someone like that to have access to a common kitchen knife, axe, or baseball bat either. A "moment of anger" or "mental health emergency" with a lot of common items in a house may not kill hundreds of people but, the carnage is still there.
The USA Safari market really blossomed when all those older Double Rifles out of England came over to our shores. I doubt there was much, if any carnage, with British Rigby and similar Double Rifles in the UK. Same on this side of the Ocean too with no reports I recall of one being used in a criminal context.
A good responsible owner could safely own a dog that many of us could not control or manage. Just because I can't, or shouldn't, own one doesn't mean I should prevent someone else from owning one. Like owning a AK-47 or M-16, there is some responsibility of the owner to prevent it falling into the wrong hands.
"Blind Bans" rarely attack the real core issue of the problem trying to be solved. An emotional "feels good" solution really doesn't help in most cases. The people that can't get an XL Bully and really want one will likely just get another similar breed. Education and Awareness would be a much better plan of attack IMHO. Big Cats are rarely legal to own as a private citizen but, that doesn't mean people don't buy them anyway. A little education about that cute cub would likely deter some people from buying one in the first place and would slow down the illegal trade in them as just one example. You achieve your goal by killing demand to acquire whatever it is your are trying to ban.