Yes, experiences vary, but that alone to me is a strong indicator we shouldn't believe the whole medical community is only after our money, and not willing to help.
Not black and white indeed.
My own mother died of cancer, and we (her immediate family) all know she could have been cured if her doctor had sent her to MRA the first time she got pneumonia instead of waiting it to renew itself the sixth time. Anyway, that doesn't mean the treatment she received is any less effective.
My father was later diagnosed with cancer, and he got cured. So experiences vary, proving all this "cancer conspiracy" talk is pretty much just talk with no substance. What we have are humans doing the diagnoses and treatments, who sadly make mistakes, and that is just a very human thing to do.
As you mentioned mistakes - indeed, these happens and I've recently read that apparently AI (computer) doctors make better diagnostics than real ones. Sadly I don't have the source anymore, but it's cool to see how technological advancements can help. :)