Because they wanna fleece you for every penny you have, but the point still stands that for the most part it's to protect baggage handlers. If you wanna take a dead body on board you have to take that up with the airline.

If you are there handling heavy items all day, you're gonna get injured. That doesn't just fuck up the workers (meaning they can't go to work) but it costs the company money too (because they need to replace those handlers).

Think of it like this, you know how the X-Ray tech has to go into a little shielded room while you are getting X-Rayed, but you are still exposed to the full force of the X-Ray? That's not because they care about their safety more than yours, it's because one x-ray is fine (what your getting), but the x-ray tech does tens, maybe hundreds a day, and that builds up to radiation poisoning.

Now replace "X-Ray Radiation" with Repetitive Strain and back injuries" and "X-Ray" with the Suitcase full of Drugs your smuggling into the Netherlands, and you get the idea.

Yes. Can't have them hurting themselves and causing delays because the airport won't staff appropriately. Remember, safety is for controlling costs.

Team lift, you're paying for a second guy to help load that.

Because they can mark the luggage has heavyweight so the handlers can use equipment to load the items.

Incentivizing lower weights in some bags is helpful. Ninety 19 lbs bags and ten 35 lbs bags is easier on baggage handlers than a hundred 35 lbs bags

Money

Right, so everyone should be allowed to bring on a coffin size suitcase with at least 100kg with of weight now? They plan that out in advance so unless you are going to inform the airline well in advance that you're bringing a corpse's weight of luggage on board, my point still stands.

"They bring bodies on board so I can bring a 100kg suicase" is a level of logic only seen when a Karen screams at some poor customer service person because her plane was cancelled due to a hurricane as if there's a secret network of hurricane proof planes that are only unlocked if you act like a bitch.

Now every single bag is overweight and they have to lift all of them all day. I suspect a few is ok but they really want to discourage too many of them so they are not lifting too many heavy weights all day.