Issues? Issues of one kind or another. No matter how open minded we consider ourselves to be. Some people might refer to them as hot button items. Whether it is religion, politics, abortion, Evolution, gays, bad drivers, dumb laws and on and on. Surely YOU have thoughts on something where no amount of "evidence" is ever going to get you to change your mind or opinion on the matter?
LOVE does not conquer all. Does it? Aren't there some things that you simply can't or won't compromise on with a SO?
Does it really do either party any good to have a conversation with a partner who has an opposing opinion? And is never going to change their mind.
Isn't DADT the simplest solution to such "problem areas"?