It's a heuristic thing. Denser objects are often* heavier, but it's the density and not the weight that may make them fall faster (not accounting for how aerodynamic a given object is). It can produce incorrect judgements, especially if they attempt to articulate their intuitive knowledge as some precise-yet-abstract law, but in practical circumstances their intuitive knowledge produces the expected result the vast majority of the time, so pragmatically it's reasonable to call it correct.
*Certainly their weight is more noticeable, as is the lack of weight of less-dense objects, so perhaps this is the real source of the skew, a type of selection bias.
It's a heuristic thing. Denser objects are often* heavier, but it's the density and not the weight that may make them fall faster (not accounting for how aerodynamic a given object is). It can produce incorrect judgements, especially if they attempt to articulate their intuitive knowledge as some precise-yet-abstract law, but in practical circumstances their intuitive knowledge produces the expected result the vast majority of the time, so pragmatically it's reasonable to call it correct.
*Certainly their weight is more noticeable, as is the lack of weight of less-dense objects, so perhaps this is the real source of the skew, a type of selection bias.