Maggin describes kal's body being as dense as dwarf-star material. Kryptonite & other things from krypton should be super-heavy on earth. No human should be able to lift a kryptonian object.
Now we're getting somewhere. I always wonder about this: it seems that Superman's weight is treated inconsistently. Bullies can push Clark over, Lois can lift his hair but not cut it. On other occasions, as Superman, he is immovable, whether floating in mid-air or standing in the path of a nuclear bomb, battleship or freight train.
I can understand Kryptonian technology having built-in, gravity compensating or defying features that allow Earth humans to use it but the same shouldn't be the case for kryptonite, Kryptonian monkeys, etc.
As well, his cape flaps in the wind.
And do the Atom and Superman have similar qualities (besides strong moral character)?