actually, the reason for shirou's "girls shouldn't fight!" attitude and why it's only present in the fate route is answered in this interview (http://www.tsukikan.com/misc/nasu-kinoko-takeuchi-takashi-urobuchi-gen-special-forum.html)

Nasu: Just like Urobuchi-san said, it's difficult to call the relationship between Shirou and Saber a relationship between a man and a woman. Saber has fought for a long time as the ruler of Britain, but then turned into a girl all of a sudden and fell in love with Shirou. It's pretty ridiculous when you think about it. But I really wanted to push it towards that sort of boy-meets-girl story. So as a last resort, I had Shirou continually say things to her like "But you're a girl," and "Girls aren't supposed to fight," in order to remind the users that "she is really a girl." It's like the author's actually the one trying to convince Saber that she's a girl... I feel like I could have written it a lot better now, but that was the best I could do at the time.