Maybe I should quote myself

He said "give consequence to young ladies who are slighted by other men" . If he was degrading her for her inferior status, why mention that she was slighted by other men? He is saying that she
is "not handsome enough to tempt" this other men. That is bad of him, but it's not different of what he had said so far. Unless you mean that he thought that she was slighted because she was inferior to those men (who in turn Darcy though that were inferior to him). (end of quote)

So I didn't said that E. was slighted by other men, I said that D. said that. D. has already made a rude remark to E. saying that she was only tolerable, so I suppose that he is saying that this was also the cause that other men didn't ask her to dance. D. of course is thinking that E. is of lower satus than his, like all the persons at the Assembly, but he's not yet concerned about her relations. (He did that when she's at Netherfield. Note that in Ch. 6, when JA said he's trying to find fault of her, only to begin to admire her, her status is not mentioned.)

JA mentions the scarcity of gentlemen as the reason that E. was not dancing. But how evident was the disparity between ladies and gentlemen? Was it of let say five or ladies for each gentleman? If Darcy saw that most of the gentlemen that were able to dance were dancing, and there were a (half) dozen of ladies not dancing, he would have to acknowledge the scarcity. But if E. and two or three ladies were seated, he could have thought that there were other reasons for that. Of course, that wouldn't excuse him for mentioning it.