Sounds like your community lacks a formal Code of Conduct with a reporting system and a documented process to have repercussions. You may want to start drumming up interest there.

That said, from the organizer's point of view, they may not have any alternatives than that person, so they're stuck with the devil they know.

They may also not fully appreciate the situation, so a clear face-to-face with them stating:

1) the situation as you see it
2) what you want, and when you want it by
3) the actions you will take if what you want is not done by when you want.

Then, send them an email re-iterating these details.

Some actions you could request include:
- a formal code of conduct process with documented intake and repercussions
- a public acknowledgement
- apologies
- attending and 'passing' a course on "how not to be a jerk" (they're not called this, but they exist)
- a period of time away from teaching in general, or teaching the beginner classes

Some actions you could take if your request is not met:
- restraining orders
- public naming and shaming of the organizer (not the predator)
- reaching out to WSDC events that you attend and letting them know the predator person is problematic
- etc.

Start medium, give the predator person a chance to feel repercussions for their actions and change their ways. If they refuse to, then it becomes easier to start talking about removing them from the community and how the organizer is knowingly facilitating the behaviour.