because she was not Mary Crawford:she was someone who knew when and to whom she could address remarks like this.

Mray Crawford is a fish out of water,and badly misjusdges her audience.

JA didn't...

And, IMO, the fact that JA could and did make these remarks( and more shocking ones too, as we are too see tomorrow) indicates that she lived in an era that did not discourage her from making them at all.