This is apparently called the “Sorry reflex”.
I’ve recently learned that “sorry!” in London at least, can mean - “fuck off/you”.
I would say sorry to someone bumping into me and not realise why but now I understand why.
“The readiness of the English to apologise for something they haven’t done is remarkable, and it is matched by an unwillingness to apologise for what they have done,” wrote Henry Hitchings in his aptly-titled Sorry!: The English and their Manners.