It just emphasized her inferiority complex.
And the fillers basically said that Hinata being the heir to the throne was to important to get hurt.
So I would assume that she would be under constant surveillance. The spoilers said that they were about to attack her.
And this was before she became a ninja
Nope, that is not what the filler portrayed. They actually showed how her father turned her back on hinata and left her to be a common village ninja. He even told her sensei to do whatever she wanted with her. It was not until towards the end of the second filler episode that he learned that her kindness was not a weakness and the Hyuga pre-destined concept was false. So in between, when she was pushed aside in favor of hanabi, there were lots of chances for her to be bullied like any other kid in the village not born into clan royalty.