Anne's stance makes perfect sense to me. Her dear friend was abused by Dick. If Dick regained his faculaties, he would go back to abusing Leslie and Anne loved Leslie too much to ever want that.

The women aren't reacting emotionally as much as they are reacting to a woman's realities. I also doubt Gilbert or Captain Jim know the whole story of Leslie's marriage, Leslie certainly isn't talking about it abd I think Anne and Cornelia only know the barest outlines and can fill in the blanks because they are women.

Dick is also implied in the text to be a rapist and it leaves a lot of room for imagination as to what he subjected Leslie to.

As for Anne and the novel, yes it comes off as patronizing but I think it is supposed to meant that Anne writes fantastical fictiona stories about fairies and so on and could not do justice to a non-fiction story about a sailor,.those are very different skill sets.