Seems to me that if there was any prior calculation from RD, it was to make sure that Labour got in.
Labour did get in with a large majority. One MP more or less makes no difference. It's not even as if she has joined another party.
I have sympathy with her Labour loyalist constituents, but they got what they voted for - Rosie Duffield, MP.
But what seems to be making some people angry is that she has criticised the PM. If he didn't want to be criticised for accepting freebies, he shouldn't have accepted freebies. And then gone on to announce benefit cuts.
She explicitly said she was not resigning the whip because of the PM's stance on women's rights, but nevertheless, people who don't think women's rights are fundamentally important are indignant about that.
Effectively, even on the most cynical reading, she did what Labour supporters told other women to do - support Labour to get the Tories out, deprioritise the women's rights issues because Labour will not (for reasons) execute their TA agenda.
So what is the problem for the Labour women?
Having said all that, I don't think there was that calculation. I do believe it was the last straw - not only bad policies but bad politics, as she saw it.