So it either sounds like you misinterpreted UW or it is just wrong.
Well, first you don't need "cardiomegaly" to have elevated left atrial pressure (aka wedge pressure or PCWP). It is that elevated LA pressure which causes back pressure and therefore cardiogenic pulmonary edema. Examples where you don't have cardiomegally but do have pulmonary edema include acute MR, severe MS, some infiltrative and restrictive cardiomyopathies, acute AI, giant cell myocarditis and many others.
Second, it is not jugular venous pressure which defines cardiogenic pulmonary edema vs non-cardiogenic pulmonary edema (ARDS) but rather wedge pressure. An elevated jugular venous pressure is very strongly correlated with an elevated wedge pressure so in the vast majority of cases you have elevated jugular venous pressure when you have cardiogenic pulmonary edema.
