... if you're very nitpicky, consider this:

the general nature of women which would lead her to adopt the opinions of the man she loved and respected as her own

Does Mary really respect Edmund? Because if she does not, this doesn't apply to her. Note that Fanny thinks Mary loves Edmund, but does not deserve him by any other sentiment - so, she does not respect him. After what we've seen of Mary repeatedly disparaging Edmund's intended profession, unthinkingly suggesting him to find another, and triumphing of having made "his sturdy spirit bend", I would tend to agree with Fanny.