My parents are the same way.
They lived in a large city for quite some time, where there were dog attacks quite often (this was over 18 years ago).
We were watching tv just the other day, and my mum saw a pitbull on tv. The first words that came out of her mouth were "eww, those are pitbills". I told her that they weren't nasty or vicious, and she continued to say how horrid they were. She wasn't talking about their "aggressive"-ness, just the fact that others have been known to attack people.
Then dad said that the pittie reminded him of Ethan. Mum got a bit of a worried look on her face and asked "You don't think Ethan has any pitbull in him, do you?" She looked terrified when she asked that!
My father confuses me on this subject. One time we saw a pitbull pup in public, and I pointed it out to dad. He said "Well, its cute now, but wait untill it grows up." I told him that I thought Pits were cute no matter their age, and he told me he wasn't meaning looks, but instead personality and all.
Another time I was with dad and talking about pitbulls, and he agreed that they could be good dogs... so... basically he confusses me on what his real outlook on them is.
I have finally got the point across that its the owner that makes the pitbull aggressive or not. I was so proud of my mum when she said that its the way they are raised that makes them what they are^^. Now I just have to convince her that not all are raised wrong.
So basically, they still think pitbulls aren't good dogs, but atleast they know that they can be raised right.

((Also, I asked mum what she would do if I grew up and owned a pitbull. Her response: "I'll never visit your house". )