This "explosion" was not actually an explosion, just an imbalance and mechanical failure.
But if I put way too much weight in the trunk of the car, and start driving, and the rear axle fails and there is an accident, yes, I'm still saying it's a user error.
(It's by the way worth considering how much weight you do put in the trunk, or perhaps more importantly, how much you put in a trailer. I transported some concrete garden patio slabs and without calculating the actual weight, put a bit too many of them both in the trunk and in the trailer. It was definitely not fun to drive.)
I think the issue here is, as many other have pointed out, that the imbalanced/weight problem for washing machines has been a solved problem for nearly 50 years. It's fine that we're moving away from all mechanical detection methods and more energy/water efficient washers, but removing the previously solved operational safety functionality just seems silly. I completely agree it's an issue of operator error, but that's not the problem - the problem is that it was a _solved_ issue of operator error that is now a problem again because it seems like there were no safeguards put in place. It would seem to me that there has to be a grand number of chances to figure this out during the QA stage for these washers and determine a simple software solution, even if that solution is the washing session cancels, drains, and the LED errors with "Overloaded" or something. The owners may be annoyed, but at least the machine isn't ruined and it can train them to use the correct load size.
Honestly, I don't think it's too unreasonable for any given person not to be able to estimate the mass of a load of laundry. I assume the recommendations (4kg, as you suggested) are educated guesses at best as it's hard to tell how much water any given item will retain during the spin cycle. Since it's an imprecise calculation anyways, wouldn't it make more sense to instead just let the machine dictate its own limits so the user can adjust their washing habits subsequently?
edit: mistyped and forgot to write "...because it seems like there were no safeguards put in place."
But if I put way too much weight in the trunk of the car, and start driving, and the rear axle fails and there is an accident, yes, I'm still saying it's a user error.
(It's by the way worth considering how much weight you do put in the trunk, or perhaps more importantly, how much you put in a trailer. I transported some concrete garden patio slabs and without calculating the actual weight, put a bit too many of them both in the trunk and in the trailer. It was definitely not fun to drive.)