My old Greyhound, Meg, was a bit of a loony when younger. Very much like a Deerhound, never grew up, always went over to say hello to other dogs, though NEVER aggressive. One day she spotted a Westie and went over to say hello, it turned on her, ripping her eye. Since that day she never went over to another dog, so in a sense it did her good, BUT, she never liked dogs near her. She would watch them like a hawk, making sure they didn't go near her, especially her bottom end, though she never growled, she just panicked.
When she was about 10, a puppy walked past us and she really told it off.
I must admit after that, it was found she was very sick with a cancer, she was 11 and we decided then and there it was time for her to end her misery, I didnt want another dog suffering like our old Lurcher where we tried everything to cure him to no avail.
My point is, get her checked, you never know, normally by the age of about 3 the dog is how you want it, if they start turning for no reason, it is usually a sign that something is wrong, after all, they can't talk.
THEN AGAIN..... dogs are animals and some people do tend to forget that, if they dislike certain dogs, they dislike them, all dogs are capable of a fight and as unpleasant as it is to witness, it is animal behaviour!