I think even today, if someone whose judgement we trust and whose motives we have no reason to doubt, told us, 'Hey, better back off, s/he's just not that into you,' unless we have good evidence to the contrary, our first reaction will probably not be, 'no, I will pursue them nevertheless, lest they think me weak-willed and spineless' because that rings of creepy stalkerism. And even today, where people of all genders have that option, there may be very good reasons why we don't directly ask that person how they feel about us and instead choose to retreat and quietly nurse a broken heart.
I rather think that from what Bingley knew, namely that 1) Darcy told him Jane did not reciprocate his feelings 2) his sisters corroborated that report 3) Jane herself had given him little indication of a genuine attachment 4) Jane's family - or at least her mother - was eager for her to make a good match, staying away was the best course of action. Of course *we* know that he should've returned anyway, but from Bingley's point of view, the chances that Jane would return his feelings were slim, but the chances for heartbreak were high, either because she would turn him down if he were to ask her directly (and there was no way for him to divulge his feelings to her without asking her to marry him), or she might accept him without feeling the same way he felt about her* (bound to cause heartbreak in a marriage later on, doubly so if he could never be actually sure why she accepted him) or, worst, the Bennets and the society of Meryton might make it known that they considered his attentions so marked that they amounted to an outright courtship, in which case he would be honour-bound to propose regardless of what he had found out about Jane's feelings so far.
* and I don't even think I would blame Jane for doing so. She might have thought she would eventually come to love him, or that they would be able to develop a friendly rapport, and he was, after all, a very good marriage prospect; she knew him to be a kind, honest man with a very comfortable income who would make a good husband and father.
I rather think that from what Bingley knew, namely that 1) Darcy told him Jane did not reciprocate his feelings 2) his sisters corroborated that report 3) Jane herself had given him little indication of a genuine attachment 4) Jane's family - or at least her mother - was eager for her to make a good match, staying away was the best course of action. Of course *we* know that he should've returned anyway, but from Bingley's point of view, the chances that Jane would return his feelings were slim, but the chances for heartbreak were high, either because she would turn him down if he were to ask her directly (and there was no way for him to divulge his feelings to her without asking her to marry him), or she might accept him without feeling the same way he felt about her* (bound to cause heartbreak in a marriage later on, doubly so if he could never be actually sure why she accepted him) or, worst, the Bennets and the society of Meryton might make it known that they considered his attentions so marked that they amounted to an outright courtship, in which case he would be honour-bound to propose regardless of what he had found out about Jane's feelings so far.
* and I don't even think I would blame Jane for doing so. She might have thought she would eventually come to love him, or that they would be able to develop a friendly rapport, and he was, after all, a very good marriage prospect; she knew him to be a kind, honest man with a very comfortable income who would make a good husband and father.