Unlike most other people of our age and experience, we are (insert favorite answer here) a) really astute students of our own and each other's hearts, b) -clear and talented communicators, c) always honest with each other, even when such honesty entails huge vulnerability for whoever is speaking, d) all of the above." Maybe.
But here I would pose the question that is relevant to so many aspects of the courtship and dating topic.
Either way, that person is now hanging on to the "friendship" in the hope of getting something more despite the "clear words" from the other person that he or she wants nothing beyond friendship.
To the extent that one person's romantic feelings have been clearly articulated to the other (and were met with an unfavorable response) to continue in some no-man's land of "good friends," is arguably to take selfish advantage of the vulnerable party. What if one person develops romantic feelings in a friendship in which no "clear words" have been spoken, such that the desires of the other person are a mystery?
I have seen and heard and read of such frustration and hurt playing out many times over.
Certainly, a man can find himself in a similar position with a woman he's attracted to, but given his obligation to be clear and intentional with the woman and to initiate the type of relationship he truly desires, he arguably has placed — or at least kept — view your "friendship"?
Yes, I know, the other person is an adult who is free and responsible to walk away if he or she is so unsatisfied, but like it or not, it tends not to work that way. Especially if it's the woman in this position (as seems to be the case more often than not) she will likely feel that if she pushes for something more than friendship, she may lose the interaction and companionship she currently has.
In other words, they tend to involve much of the type of intimacy and companionship involved in — and meant for — marriage.
As you probably know, I believe Scripture to teach that engaging in the types of emotional intimacy and companionship involved in close male-female friendships — outside of marriage and for their own sake — is wrong (see else I've ever written for Boundless).
But even if you don't accept that premise, such intimacy is still inadvisable in the sense that it delays and discourages marriage, which Scripture unambiguously calls good and right.
Basically, the question seems to be how exactly single Christians should relate to members of the opposite sex in that large and awkward zone between "we've never met" and a deliberate dating or courting relationship. I won't repeat the full history lesson here, as several Boundless authors have already discussed it (Joshua Rogers most recently, in his excellent piece "Your Friendgirl Deserves Better").
Essentially, the historical reality is that until 30 or 40 years ago, long, intimate friendships between men and women in which each served as the other's emotional confidante, relationship adviser and "best buddy" were far less common than they are today.