Someone should tell that to US government. The first internship that i had in a (state) government office would do early dismissal when the inside temp was over 90 degrees for 2 hours. It was a miserable experience.
I honestly find working to be harder in that environment. German summers are traditionally not that long, but still it's two months of lower productivity.
There is one benefit though, shorts and sandals is accepted as office clothing.
I live in a country that uses traditional brick and mortar construction and I can tell you that American homes are far easier to condition climatically.
It’s possible to build buildings that are reasonably comfortable in high heat. It just costs more than a generic box with AC.
You can get away with no A/C a lot easier if you're almost in the Arctic circle. In reality I bet this rule has a fairly minimal impact on energy consumption because the buildings didn't need much air conditioning to start with.