Of course - there is always a way to block a specific user or IP. The problem is that the time & effort per site/proxy to do the blocking would give you a huge requirement of SMART manpower to do the blocking.
Now - in my experience, Government never employs the SMART people - so you'll have the people of below average ability attempting to block people who are smarter and more motivated to get around the blocks.
Anyway -regardless of the effort the Govts put in - whilst you are at the point where it takes human discretion to decide what to block, you will face the insurmountable problem of needing thousands of people just to maintain the list of blocked sites/IPs. That alone makes it impossible.