He shouldn't have suddenly closed your account, I agree. What is the issue with you handing over a bit of info though? You don't have a problem posting a picture of yourself publicly. A verified email, name and address isn't so bad.
What is he going to do with my passport? I do not know his policy. He has not made it public! He has no terms of service!
"We may at our discretion, ask asset creators to provide proof of identity, address, phone number and more, until we are sufficiently satisfied. Said information will be held securely offline and not shared with any third party. We reserve the right to freeze trading of the asset and the asset creators account for failure to provide requested details or in the event of suspected fraud. "
Seems like half was done.