We, men, cannot do so, again with rare exceptions. If I enjoy spending time with a girl, if I am interested in her, if she is also sympathetic to me externally (and it follows from the story given that the girl previously had a relationship with guys she now just wants to be friends with), then I will not be able to just communicate without trying to translate the relationship into a closer plane than friendship.

A man should not attribute his sperm to the whole half of mankind. There are a lot of very selective men who do not rush to drag into bed any girl with whom "interesting and cute". Oh yes, so there would not be so much irresponsible love in pleasant, interesting and cute girls, who have to limit themselves to friendship.