Visible but disabled items are only useful if they can be enabled in a more-or-less obvious way. Showing a disabled item that you can't enable in any way is bad UX. Am I wrong?
Knowing that Apple is preventing you from accessing it gives you a way to enable it again: By pressuring Apple to stop doing these shitty things. Same thing with displaying Apples 30% app cuts, if it was clearly shown everywhere likely people would pressure Apple to reduce it which is why you aren't allowed to show it.
Edit: Reading the article again, there is actually a very simple fix to view these posts: Go over to your friend with an android and access them to there, and then remember to buy android in the future to avoid censorship like this. This is surely the main reason Apple doesn't let them show this note.
A notice is not a disabled item. It's information. It would only be disabled if it was visible but the text was obscured. 'Enabledness' in the context of a notice is legibility. The intended user experience is reading the notice and understanding more about the world.
You are right this time and now you know why Telegram put those messages there: to allow users who need those messages to go online on the Internet or swap to an Android phone.
Edit: Reading the article again, there is actually a very simple fix to view these posts: Go over to your friend with an android and access them to there, and then remember to buy android in the future to avoid censorship like this. This is surely the main reason Apple doesn't let them show this note.