I am in total agreement with much that you say here Peter. Maybe it's a male perspective based on our own opinion as such, because Darcy's behaviour is completely devoid of any sympathy in males that romantic feelings may inspire in a woman. Based on his behaviour at Meryton in fact, most males would hardly want to associate with him socially at all. We, as readers, know little or nothing of him in depth beyond his warning himself against falling in love and sulking moodily by the windows and in corners when visiting. As to his meetings with Lizzie, we know even less beyond some brief descriptions passing encounters and short conversations in the mananer of strangers. As you so rightly state, his proposal (which is again only briefly described verbally by the narrator) indicates a great favour being bestowed by its very offering. The saying, "Handsome is as handsome does" comes to his rescue in his actions in resolving the Lydia sitution, but would he have done the same for anyone else without his desire to do something for someone he was almost obsessed with? Did he have in mind to resolve Lizzie's worries by removing them so that she could return to normality? Did he have anything to do with Bingley's convenient return to Netherfield in time to accompany him on visits to Longbourne?
Jane Austen didn't waste many words on physical descriptions of her characters to let actions speak louder than words, as the saying goes, and, in the case of the primary males in Pride and Prejudice, little time even on them at all. Bingley disappeared from the scene entirely for eight months and Darcy flitted here and there appearing only in mention when Lizzie was involved or related to her.. It does give us licence to use our imaginstions (even if a little wildly at times).(-:
Darcy, is effectively a mystery man that we know very little of.