Out of curiosity what do you mean by censored? Are there groups that cannot be listed on the iphone app?
https://upload.wikimedia.org/wikipedia/commons/2/2a/Telegram...
The exact message you see is "Unfortunately, this channel couldn't be displayed on your device.". It doesn't say anything about the app store because apple policies don't allow apps to say that contents are censored because of apple guidelines.
These same channels survive on Android so far.