Surely, you have to admit that he at least encouraged her headstrong behavior. Every time she showed "firmness of character." she was rewarded for it: "I honour you!" ... he spoke with an "earnest tone" ... "with such serious warmth!" (ch 11)

And he had also encouraged the whole "jumping down" action: "all their walks he had had to jump her from the stiles; the sensation was delightful to her." (ch 12)

Of course he didn't mean for her to be so stubborn that she would put herself in danger, but can't we always forsee the effect our words and actions will have on others. In his eagerness to approve "firmness of characters" - as a direct reflection on Anne - he did not temper it with common sense. I love Anne's thoughts when they are traveling back to Uppercross:

"Anne wondered whether it ever occurred to him now, to question the justness of his own previous opinion as to the universal felicity and advantage of firmness of character; and whether it might not strike him that, like all other qualities of the mind, it should have its proportions and limits. She thought it could scarcely escape him to feel that a persuadable temper might sometimes be as much in favour of happiness as a very resolute character." (ch 12)