I don’t think this is true. I personally know of a case in the UK where due to a false report of a gun, an armed squad was sent to someone’s house.
It may not be discussed as casually as it is in the US, but every country has armed police and they deploy them when they expect guns to be involved.
It’s just false to claim that swatting is a US only phenomenon or a function of police culture.
https://www.newstatesman.com/sci-tech/2015/08/swatting-uk-tr...
The use of armed police there is a big deal though. My friend is a police officer in the UK and has a firearm and riot gear for armed responses, and they very rarely use it. When it is used, there's loads of reporting to ensure its use was justified.
I am an investigative reporter covering US law enforcement and crime. Let me know if you'd like to see some examples of the documentation I am referring to.