Bob Ewell is a man without principle, dignity, self-respect, nor purpose. He is basically an empty, broken bad excuse of a man. He is a social misfit.
This being said, it is therefore impossible for him to feel respect, or seek for the preservation of dignity of anyone else, even if it means his own family. We already know that he neglects the family by being a drunkard who allows for his family to continue multiplying even living in the junkyard where they live. Therefore, for he to speak that way about his daughter is not surprising.
What his words imply, first of all, is that he has no respect for his daughter. He sees her as just about any other woman and, for a man like he, a woman is basically a second class citizen; so this is the same view of his daughter in his eyes.
Second, he compares his daughter to an animal, a "stuck hog". What man in his right mind would speak of a woman this way, especially of his own daughter? We can certainly see a profile of enmeshment, lack of respect, a break in boundaries, and a dysfunctional attachment between father and daughter. This implies more abnormal behaviors such as incest, inappropriate communication and so on.
There is too much one could say about Mr. Ewell's ways, but the one thing that is consistent is that he is, indeed, a sore sight in Maycomb.