I like the 'much like teenagers crying over the marriage of a famous pop star' - I think that's exactly the sort of feeling they were feeling !!

At this point Lizzy condems Charlotte partly because, as you say, Charlotte hasn't acted in the way Lizzy would and had acted. But Lizzy's views or standards here are also somewhat naive, as she ignores that fact that both Charlotte and herself and her sisters have very few options other than marriage to preserve them from 'want'. In both families the financial future is not certain, which Charlotte appears to acknowledge but Lizzy does not.

Jane's views are more reasonable, though she too is initially surprised by the match - "You do not make allowance enough for difference of situation and temper. Consider Mr. Collins's respectability, and Charlotte's prudent, steady character. Remember that she is one of a large family; that as to fortune it is a most eligible match; and be ready to believe, for everybody's sake, that she may feel something like regard and esteem for our cousin."