I think maybe it was mostly due to him being a jerk as opposed to any religious preference.
Exactly. Islam actually states that in order to prevent permanent physical harm to a woman, it is completely acceptable for her to be examined by a male doctor. In fact, her husband is obligated to do whatever he has to do to prevent any physical damage to his wife.
A lot of times though, a man will just use religion to justify his aversion to any man seeing his wife undressed, regardless of the situation, while he really does not know much about the religous aspect.
There are general rules in Islam, but there are always circumstances when these rules do not apply. For example, eating pork is forbidden in Islam, but if you are stranded on an island and the only food available is pork, you are allowed to eat it to survive. There is a general rule of no contact between men and women, but in cases of medical need, these rules do not apply.
A lot of Muslims themselves have a misconception that is forbidden to donate organs, because desecrating a dead body is forbidden. While it is a general rule to not mess with dead bodies, many scholars in Islam have stated that in general you should not mess with bodies, but when it comes to trying to gain medical knowledge, or donating organs, it is not the same as just cutting up a body for no reason, and that donating organs is fine. Many clerics in places like Saudi Arabia are trying to spread this message to increase the number of organ donors cause they have a huge shortage due to this misconception.
This does not come from a 21st century, modified version of Islam either, these are actually orthodox principles in Islam.
As far as Muslim women in the medical field, if they feel thay they can not have any contact with males then they certainly should not enter the field, at least in the US. There are medical colleges for women in the middle east. They are entitled to their opinion, and shouldn't be criticized. But if a Muslim woman decides to practice medicine in the US and feels that any contact with men in a medical setting is permissible according to Islam, then she has legitimate reasons for believing so as well.