the Public Bank of China is trying to put an stop to not regulated bitcoin exchanges that have been reporting that they are handling billions of dollar every day and that is a big red flag for any government regarding money laundering and other criminal activities and it has to stop.
and in the end these exchanges will come back and continue but this time they will cut any money laundering and any other concerns about legality their government had.
Maybe he is just trying to used Analogy here. Great Wall of China=Great Firewall of China. I don't think that PBOC can stopped the Chinese or any nationality to do trading and investment with other cyptocurrency or localcoins as the OP says. They will always find a way outside of the censorship to earn or profit because people need money to lived. So it doesn't mean that since PBOC has regulated or suspended the exchanges now, you will cease your trading as well, no, just find a way outside of it and continue to profit everyday.