I can't see her.
Besides: as far as I could see I didn't have an alternative to outing myself. If I hadn't they would have found out from one of the three other people who were going to tell them, if not my own parents.
She will learn the truth in due time, and when she does, she will have to stick up for her right to see me. It isn't pressure at all. The decision is hers to make.
Even if I could propose, what would that accomplish?
Her parents would just think I'm even more crazy and double down on excommunicating me.
If I can think of another way to stop this foolishness, then by all means, I will. Otherwise, it will come to an end on its own when they are no longer able to keep her in the dark. If only I could contact her... but I presume you agree that it would be better to not do that under the threat of her mother calling the police and her being interviewed. Come to think of it, if I managed to contact her with a proposal, why would the outcome change? Are they suddenly going to recognize true love and backtrack on everything because she feels the same way? Should I just tell her parents that she feels the same way and argue to have her feelings considered? But that involves telling her parents about all of HER propositioning, which, again, might just be another cue to start an investigation.
I'm not too worried about her losing respect for her parents. She didn't have much in the first place... and especially after this, they don't deserve it.