Ha-ha! :lol: I just now got your OP here in this here thread! Had to study it several times to really get it. Usually I get stuff like that easily but you posted a good one! (Between the title, text, and photo of hot charger on ice.)(and photo caption, now that I noticed it)
IDK for sure but my guess is those entry-level commodity chargers get quite hot because they have no internal cooling fan to conduct away the heat generated. Another guess is that the next level up commodity chargers that have internal cooling fans generate just as much heat overall but stay cooler to the touch because, well, the internal cooling fan is dispersing the heat. Yes wasteful. I have some of each. One (non-fan) charger that runs quite hot is stock issue from a large well-known ebike mfr. (Rad Power Bikes). On their forums they state that is normal and not to worry about it-- "They all do that."
BTW the other ebike forums I have visited are not as good as this one, technical, truth, and concise-wise. Maybe you have found better? If so, please share.
Another BTW, several of my laptop chargers and powerbricks also run almost as hot, what's up with that?