We developed shadowsocks for the exact purpose of battling machine learned DPI head on.
The real challenge is the (poor) quality of the networks and the topology of censorship body all around China. The Blackbox nature of such state system made each improvement feel like experiment at best, simulated annealing at worst.
1. shadowsocks is a good example that certain vpn/proxy can survive after becoming popular. 2. GFW blocks sites/pages/connections based on content, it has been doing this for more than a decade. whether shadowsocks can fool GFW or not doesn't change the nature of GFW.
So, 1. Chinese gov don't care about those who just want to paste a photo on twitter, they blocked website such as twitter because it's known by even some Chinese farmers or workers. They are supposed to be susceptible, which means, danger.
2. It is said that China will block by whitelist instead of blacklist(maybe like North Korea), but they didn't do that.
3. Usually, someone who can buy and setup a server for himself is clever enough to distinguish between lie by terrorists and the truth.