Why the hell would they? They have no obligation to prove the rest of the world right or wrong of their doings.

Are you equally surprised the USA gov isn't letting other nations to come inspect all the south American refugees they have locked in cages? Not to mention allegations of sterilization and torture in these prisons.

https://www.npr.org/2020/09/18/914465793/ice-a-whistleblower-and-forced-sterilization

Not to mention the USA and Canada have genocided and brainwashed the natives of north america and have yet to provide any meaningful reputations to them. Even worse they continue to oppress these minority groups, which only happen to be minorities because they've killed off the majority of them.