"You know how I detest it, unless I am particularly acquainted with my partner. At such an assembly as this, it would be unsupportable." - chapter 4
"I certainly not have the talent which some people possess (...) of conversing easily with those I have never seen before. I cannot catch their tone of conversation, or appear interested in their concerns, as I often see done." - chapter 31
He is very "closed" to whom he doesn't know well, even if we don't have an occasion of seeing him in a "superior circle" where he knows nobody. And rather talkative, though speaking with reflection, with people he knows, not only with sensible and pleasant people (Bingley, Elizabeth, Jane, Charlotte, Colonel Fitzwilliam) but also with silly, unpleasant ones (Bingley's sisters, his aunt...) and this, whatever their rank or consequence - at least, among gentlemen/ladies.
And when he seeks the acquaintance of Elizabeth, he tries first, at the Lucases, to catch her conversation with others, in the hope of, later, being able to speak with her; and is upset by the dancing interruption.
I don't understand how you can believe that making acquaintances is not difficult to him.