Why does the max weight for a checked bag depend on the destination? Is that due...

I read on https://www.delta.com/us/en/baggage/checked-baggage/excess-overweight-baggage regarding overweight, checked bags:

If you’re bringing overweight bags, review the following. For more details or to find special policies for items like medical equipment, instruments or sporting goods, review Special Items and Fragile, Bulky or Other Items.

• On flights within the United States, Canada (including the U.S. Virgin Islands and Puerto Rico), bags 100 lbs. (45.36 kg) or more are not allowed.

• On flights between North/South/Central America and Europe/North Africa, bags exceeding 70 lbs. (31.75 kg) are not allowed.

• On flights to/from/within Australia and New Zealand, bags exceeding 70 lbs. (31.75 kg) are not allowed.

• On flights to/from/through Europe, South Africa, or United Arab Emirates, bags exceeding 70 lbs. (31.75 kg) are not allowed.

Why does the max weight for a checked bag depend on the destination? Is that due to the airport, local laws, local partners, or something else?

I am asking to know if that means, for example, that flights to/from/through area/airport/etc. will never accept a bag over 32 kg (e.g., flights to/from/through from Europe would never accept a bag over 32 kg).

It's possible the answer will vary across countries/airports, however in many cases the limits you've mentioned are attributed to Occupational Health and Safety (OH&S) laws in the countries in question.

These laws generally won't dictate the maximum weights themselves, but instead require employers to have in place a maximum amount that a single person (or two people working together) are allowed to lift.

For many years the airline industry has used 50 pounds (23kg) as a standard for normal bags, and 70 pounds (32k) for 'heavy' bags (which would frequently require an additional charge due to their extra weight). Many airlines and affiliated companies (such as ground handing companies like Swissport and Menzies) thus codified 70 pounds/32kg as a maximum weight that their staff could handle in line with OH&S regulations.

In some cases heavier bags are allowed if they have wheels such that the staff do not need to lift/carry them, however normally this exception is only applied to things like wheelchairs and similar devices.

Many airports have subsequently also restricted the weight of bags allowed on their baggage systems to 70 pounds - although it's unlikely this is actually a system limit but more them falling in line with the airlines/etc limits.

Larger items can be sent via cargo, as cargo carriers generally have lifting equipment available to be used for these larger items, removing the need for people to lift them.