When Jane comes downstairs for the first time after being ill at Netherfield, "(Darcy) addressed himself directly to Miss Bennet, with a polite congratulation; Mr. Hurst also made her a slight bow, and said he was 'very glad'; but diffuseness and warmth remained for Bingley's salutation." John Moore likewise behaved correctly, but without the warmth that would endear him to others. Like you, I hope there will be more clues as to why he was so disliked!