Maybe this is true for some IMGs in private practice, but not all. I've met a path IMG who had amazing stats/record (USMLE in high 250-260s and 3 first author pubs, a record that's far better than mine), and she said the only reason she aspires to working in the US is b/c of the research potential here. That is, she wants a lab, and a high-profile one. As a matter of fact, she clearly stated that IMGs who make it to the top programs here are usually selected for certain reasons. For her, she said her income would be higher back home (factor in GDP, buying power, and the amount of $ she can save, I believe), and she will have no problem hiring a full time maid, nanny, and possibly even a driver. On the other hand, her income here won't even allow her to buy a nice abode in more urban cities back home, not to say she won't be able to afford having nannies, etc, here.
From what I see, she is very far from being clueless, and she certainly understands what type of salary is acceptable in the US. However, when you are looking for academic jobs, I think young trainees have very little bargain power in the academia. That is, she can only take whatever is advertised or offered in the dept. I wouldn't blame poor academic salary on some IMGs being clueless. Something else must be done. The academic salary is bizarrely low for path, even when compared to other specialties that traditionally have many IMGs (neurology, IM, FM, psychiatry etc). I think young pathologists need to take more active steps in demanding for better compensation, esp since pathology is a money-making dept in the hospital. I don't see why pathologists don't deserve more.