In Ch10, first paragraph, we have the following:

It was the highest satisfaction to her to believe Captain Wentworth not in the least aware of the pain he was occasioning..... He had, probably, never heard, and never thought of any claims of Charles Hayter.

These are Anne's thoughts, and she could be wrong about this. But if she is right then it is hard to see how the Captain is blameable for ruining Henrietta's chances with Charles Hayter.

Surely the blame for that should lie with Henrietta or, if she is too silly to realise what she is risking, with her parents who should have warned her instead of leaving things to chance.