I've spoken to several friends that hunt, and even when they are just following a pre-laid trail it's still called a hunt, which in my opinion is where a lot of the issue comes in. People often get all offended by hunts were a fox isn't even being used.
In this case we've no idea what caused this escalation. What we do know from past experience is that both sides get charged up, there is the expectation of conflict between both sides and things can often get out of hand. Maybe she was charging people down, maybe she was worried she was surrounded by sabs and was purely defending herself and her horse. Ideally, they all need to grow up a little.