I'm not the poster to which you were directing your question, but the reason I wouldn't want either of my children to join the military is that I am a pacifist and come from a long line of pacifists (my maternal side of the family has been in the country since 1682 and no member of her family has ever served in the military). My wife and I fundamentally disagree with the intent and direction of the military and therefore, my child joining the military would disappoint us because it would be a departure from the values I am trying to instill in them (although I would still love them unconditionally, and at that point I'd encourage them to pursue management in a non-combat capacity). I have other concerns about the military, as well, but they are subordinate to my overall values and stating them would invariably lead to a debate that would violate the rules of the forum.
As to the "southern gentleman" thing, I think that is a cop out (although I think the prevalence of that belief points to another of my concerns about the military and the military industrial complex). Firstly, if the male cannot follow the orders of his commanding officer and insists on thinking for himself, then HE is the issue and not the woman and HE shouldn't be in the military. That is the whole theory behind the military, i.e. the ability to follow orders (and another major issue I have with the military mindset), and therefore if the male chooses to disobey that order, what other orders will he disobey? Secondly, manners are not in one's DNA, so "centuries of training and upbringing" is not accurate or relevant (even if it was true, which is far from universally agreed upon and certainly would be disputed by me). If the average enlistee is 18, then he or she has been "trained" by his or her parents and role models for 18 years and he or she needs to make the decision to follow the instructions of their military commanding officer or follow another career path.
Personally, I think the selective service should be eliminated as a whole, as if we ever need mass enlistment again, I'd hope the civilian leadership of the military would be more tactical about their approach and not just look for mass numbers of forced enlistments.