Well I think you only have one choice: withdraw her from college.
You say the teachers are rude and just take time off whenever they want to- that's totally unacceptable.
They treat her like a child and are trying to prepare her for work and take on the role of social workers/parents. That clearly upsets you, you won't change that. Best remove her.
You want her to be able to attend when you want and not be reminded of attendance or punctuality. If she is homeschooled you won't receive another letter ever again.
She is doing really well, is well motivated and doing better than anyone else- so she'll be fine teaching herself and carrying on with the tuition.
Or you could take a long hard look at yourself, consider how YOU asked for help and advice, we're given it, and then argued with everyone pointing out the flaws in your logic.
Think about what example you're setting for your daughter who is about to embark on an independent life, about rules and authority and following instructions.
Nobody is perfect, your daughter has had a lot of time off. Period pain is not a reason to be absent- if it is that bad you must send her to a doctor. If she had a job, she'd be dismissed by now. A teachers job is much more than just preparing them for their exams. It IS preparing them for society, working, further education, family life- the lot.
I feel sorry for the teachers you are dealing with. You sound like an utter nightmare to reason with.