Why do employers in USA and Canada get less annual leave compared to UK employers?

I came across two Police Departments (1 in US and 1 in Canada) offering 15 days annual leave for new Officers. After 10 years service the annual leave rose to 23 days (with no mention of separate additional public holidays).

Here in the UK, or specifically (Police) Scotland, new Police Officers will enjoy 28 days annual leave entitlement, which rises to 31 days after 2 years service. In addition, Officers will also get 2 statutory public holidays for their leave.

The difference is obvious.

I know it's just comparing 1 sector but it prompted a quick google search where the consensus was that American and Canadian companies/organisations gave less leave for their employers compared to what is offered here in the UK and I was just wondering why that is? Is it cultural? Is there an emphasis to be at your job more often than not? Or, is a generous annual leave package not necessary because you get given a good amount of rest days?