Hey Bin, I just responded to Marya. I think it may be an image used from Flickr that got flagged. Flickr default copyright rules are All Rights Reserved. Explicit permission from the image owner is needed to use it and Medium takes copyright fairly seriously.

Of course, this is only me looking for anything that might have gotten her flagged. I can't say for sure if that is what happened.

Edit: I've looked at the other's here who have stated they've been revoked. Except for 1, they all have some type of issue with crediting images. Images from Flickr, images from Pinterest, images without a credit at all. Without a confirmation from the source that the images are Creative Commons/free to use or permission to use them, they shouldn't be used at all. It’s the only common theme I can see amongst those who have commented here that they’ve been revoked.

Someone else mentioned improper tax/payment information and that's a good place to start as well.