It's clear even Elinor could find no "drama queen" acting in this scene! She cries quite as much with Marianne. As she says, this amount of emotion is shocking...but also necessary to be shown, or it will be repressed.

I do wonder if perhaps J.A. was contrasting this type of grief with Marianne's formulaic reaction to Willoughby's leaving Barton in Chapter 16. As Peter Leithart mentions in the book "Miniatures and Morals", there is nothing satiric in Austen's description here. She has called us all to have a good laugh at Marianne with her overly dramatic flourishes, then hit us in the head with a view of *real* grief.