Really? My girlfriend and her friends would strongly disagree with that statement. From my understanding they grew up in a time when internet in China was a lot younger and they actually had an ability to discuss political discussions, or items that highlight the government in a negative manner.
Now everything that isn't the government's view is incredibly censored/filtered online. It might hard to not see the erosion of freedom when it's being prevented from being communicated online.
Fwiw I'm not disagreeing with your statement on economic freedom and I find the amount of people lifted out of poverty and the growth China has gone through in the last few decades to be incredible but it seems a bit disingenuous to say certain "freedoms" haven't been eroded in the last 10 years comparatively.