It's not very good parenting, no. It seems like she is so mad at your dad that she doesn't realize that you still love him as a father, or that she can't cope with that fact. It's quite normal for people who are abandoned by their partner to get bitter and resentful and this sometimes is taken out on the kids. But that is unfair! And she has HIT you, which is unacceptable no matter what. She probably wishes you cut all ties with your father and took "her side", but she can't demand that of you just because her feelings are hurt. I think that is why she gets so angry at you. She needs to realize that even though he left you he is still your father and you want to stay in touch with him, and that she's acting a bit selfish because she puts her own hurt feelings above your well-being.