Just a caveat, there's some difficulties inherent in trying to sum up a situation like this, without seeing the dog.
With that said, you've given what seems to be a very clear picture of what is going on. By the end of the description (what kind of cookie do I get?), I had a pretty precise image of Sally and some of the possible underlying personality traits and weaknesses that are causing you a problem.
To directly answer the question in your topic subject line. I think "Confused" actually is an excellent description of Sally, at least the first link in the chain. Yes, I know you meant you! The other two things? Well, meh, I'm not into categories like those, although I do use terms like that as shorthand. In this case I don't think they are useful - I least I wouldn't start in either of those places looking for answers.
The Reader's Digest version of the following is that I agree with those who recommended measures to increase her confidence. I believe you should start at home and look for small scale ways to do that, however.
Sally has limited dog on dog social skills. That's where she starts - and it's a natural thing for a pit bull - they were never intended to be canine team players. She's like the kid in school with a KICK ME sign on her. And she knows it, after her first few experiences in life with other dogs.
Just like that nerdy kid with the chip on his shoulder, she has learned that the best defense is a good offense. Failing a good offense, which she really doesn't have, just being ON the offense all the time, is a natural next best choice.
Some of this you may never alleviate beyond being simply manageable. It's probable that she will never be a dog you can allow to socialize with other dogs. BUT, a reasonable goal is that she will pay more attention to you than to another dog. Unprovoked attack is NOT a breed trait - pibbles are not supposed to have hair triggers.
With that in mind, back up your training and work her obedience in the house, out of the house, at random times - and try to think of new ways to include her in your activities. Does she know "tricks"? Really up the ante on her training. Make yourself the most intersting thing on earth.
After that, slowly test the boundaries of her tolerance. That point when she turns from you to another dog - that's her telling you that she doesn't fully understand her job yet. She doesn't trust you 100% to take care of that other thing in her life.
Make it easer and ask again, then tell her with clicks (if you clicker train) and her favorite rewards and gentle CALM praise, that she is wonderful. Ask a few more times, then increase the difficulty again. For a dog that's really having fear and communication problems, I like to mark the message a dog sends me that they are not ready for that level of difficulty (by disobeying), with a quiet, "Oh well."
One of the problems I have with trainers and what I often hear about them (I'm often the person they call after they've "done everything" and "even called an in-home trainer.";) - I know they only have a limited amount of time, but instead of demonstrating a technique and assigning homework that will get you somewhere, it seems like many of them want to be the next Cesar Milan and solve the problem in one or two passes.
This will take a long time. Start the first step and plan not to expose her to any dogs, any more than necessary, for a couple of months. Yes, that was months - that's how long it takes a behavior to move from the lobe in the front where conscious thought lives, back to the place where it becomes more or less automatic, and can override even strong emotional or autonomic based behaviors.
Likewise, divide the task of paying attention to you in the presence of other dogs, into smaller chunks, which you'll also spend a couple of months reinforcing before you move on. For instance, get her sound in the presence of dogs she knows and trusts more, dogs she's not familiar with but are like dogs she trusts, young dogs of the opposite sex, and so on and so on.
Ultimately, the highest goal would be being able to handle her OFF leash around dogs she already dislikes. But it's not a failure if you can't get that far with her. In fact, every success is a success in itself - one step closer - and the more you can build up, the more you'll have to build ON with her.
I hope this make sense. And you get a Dove chocolate if you have read the whole thing. :D