Dr. Sloper, a kitten drowner at heart, knows what his daughter should do and indeed, were she a kitten drowner too, it would have all worked out for the best. But instead, she is too sensitive and is hurt by everyone. Her sensitivity is all she had going for her and when she learned not to trust it, she has nothing going for her. In a tragedy, the protagonist's flaw leads them to disaster but the reader gets something out of it. Here, the father prevents that from happening and no one gets anything out of it.