So, if conversing well, especially in order to please the ladies, as your quote indicates, is at the heart of gentlemanly behavior, I think we can at least say with certainty that that part of gentlemanly behavior was of little importance to him. He was certainly rude at the ball at Meryton. The only real question is his motive.

Perhaps, like Mr. Bennet, there is a tendency not to exert himself if he finds it inconvenient. I think he cared more about pleasing himself than pleasing the ladies. I think he was tired of the Caroline Bingley types, who were continually trying to gratify their vanity (or marriage hopes) by engrossing his attention. It did not gratify his vanity to be fawned upon, so he would rather remain aloof.