Maybe some parts of AWS are blocked in China some of the time in some places (the Great Firewall is not applied very consistently), but I have used AWS servers to play around with deep learning; connecting from China without a VPN worked fine.
Since Amazon probably uses most of their services themselves for their Chinese site, I'd be highly surprised if there were any large-scale bans in place. (Maybe you are thinking of Google Cloud?)
One thing to keep in mind that AWS wasn't as perfect at the beginning either. Maybe it's fair that the Chinese are giving their own service the same pioneering freedom as AWS had when it started. This isn't the part that confuses me, the part that confuses me is why isn't US reacting to all these bans, even now with Trump
AWS is not blocked but there are some inexplicable restrictions. Even with full licensing, you can't host a website on S3. And a ton of services are missing. Even SES which per the usual makes no sense. Welcome to the jungle.
