The sad fact is that oppressive governments don't really care. A few geeks who can pierce the firewall are no threat, the government just needs to choke the internet enough to prevent the general public from organising.
Fortunately for people who care about the health of the internet, I doubt that the Sri Lankan government has the technical acumen or sufficient budget to operate anything similar to the Chinese GFW's DPI abilities.
Speaking of shadowsocks, I really feel sorry for the author.. I believe his final words were "I hope one day I'll live in a country where I have freedom to write any code I like without fearing"