I'm surprised no one has done their homework on this issue. A few days before this move, the CCTV (party TV of China…voice of the government) reported on the dangers of mobile pornography. This was similar to a report issued about search engines used to access adult content. What happened? A few days later Google was briefly shut down and traffic redirected to Chinese search engines.
It doesn't take a policy wonk to realize that the government is about to crack down on the mobile Web and when it does crack down, it targets foreign companies.
So then they make the move. And you expect them to criticize the government and expect things to be smooth sailing afterwards? Not a chance.
I should point out that the message they give is not a lie, in fact. Presuming the servers are located within China, speed will be improved for Chinese users.
What you would like them to do is blame the Chinese government. Google did it, maybe Opera could get away with it. Maybe they couldn't. What would you do if Opera did criticize the government, and then Opera Mini was shut down? You would probably cheer Opera's stance and then go download another browser.