I dont see anything "impure" in the things that most of the characters want such as wanting love or to marry -or even in Col Fitzwilliam's case, wanting to marry a woman "with some attention to fortune".

...Charlotte is at fault not becauase she marries a man she does not love, but becuase she marries one she does not respect or like, and she deceives him about the nature of her regard in order to get him to propose.
As for "toadying", I dont see that it is SO appallingly bad, certianly not as bad as some things that people do, but it certianly isn't behaviour that Austen approved of, especially when done in the OTT way that Collins does it..and while Charlotte's behaviour is as I've siad problaby more tactful and politely and skilfuly done than Mr Collins' attempts at it, she still certaianly must defer to and flatter Lady C, since nothing else would work with her...