I would be very surprised this being just it, the chance of them finding out about obscure chat channels in a country across the ocean without somebody from Apple having a job monitoring them full time is infinitesimal.

This very much reminds me how Google disappeared websites of Russian opposition (weeks after signing some memorandum with kremlin,) and then told "maybe they need to improve their search engine friendliness?"

Oh, I wasn't suggesting that Apple monitors them or actively looks for doxxing, but that somebody (potentially from the police) informed them about it, they took a look and concluded that it's against their policy.

I don't know whether that's a common thing, and I expect many companies wouldn't go the Telegram route and publish the demands because they don't want to put stress on their relationship with Apple.

Discord apparently has channels that are used for similar activities, but I don't know whether Apple has asked Discord to hide those channels from the app, or whether anyone complained to Apple in the first place.

For as long as I know, it's explicitly legally forbidden for private parties in US to engage in foreign relations.

So, "even" by the word of US law, Apple has no permission to engage with Belarus government.

I don't think somebody reporting content for policy review (Apple's content policy, not foreign policy) is affected by any US laws. That person wouldn't have to be an Apple customer, they wouldn't have to be a user, they wouldn't have to be outside the US.

I doubt there are any laws that would forbid Apple from taking or acting on a report of content policy violations.

It probably is just about doxxing, but it still shows how scummy and so far up their own ass Apple is. Just think about the lenght of the reach - trying to regulate what content somebody on a messenger app should post, not even social media platform like twitter/facebook (do they monitor those too? Telling them which groups to have?) They feel like they're creating their own little world, their own universe. And it's not some unambiguous situation like posting nudes of your ex gfs, it's very complicated what's happening in Belarus, at the very least they shouldn't interfere. But they couldn't care less about democracies of the world, if there's a slightest chance that Apple very very remotely might burn - they're OUT. And on top of that they want you to be clueless about it.

Now, take a deep breath, and think how realistic that prospect is.

the Belarus government is very popular in Russia ;-)

With the government, certainly. Are they also popular with the people, that is, would anyone switch away from iOs because Apple stood up to Belarus?