Those quotes yes, but they are taken out of context. The actual letter they are taken from is talking primarily about the technology.
For example, this quote from the OP
"Rather than silencing a voice, the result is depriving the population of material they can see and read. This is censorship, as it skews the way people see the world."
Alongside the OP's comments it reads as though they are saying that blocking porn would be depriving people and censoring people right?
Here's the full quote
"On the Internet, censorship has taken a new guise. It doesn't merely prevent publication, but also restricts people?s access to the information they seek. Rather than silencing a voice, the result is depriving the population of material they can see and read. This is censorship, as it skews the way people see the world. It is tempting to regard filtering the internet as a quick and easy way to restrict unwanted speech, opinions, or media, which the government regards as harmful for either them or the people. The right to see the world as it is, is critical to the very tenets and functions of a democracy and must be protected at all costs"
This paragraph is not about porn, but about the technology being used to silence views that are in opposition to whoever controls the filter. One of the big fears with a centralised filter is the ease with which it can be abused, because so far that has happened with every single centralised filter.
Or this quote from the OP
"The current discussion of blocking pornographic content has offered no definition, no evidence and suggested no technology. This is an affront to the basic principles of the society..."
The full quote?
"The current discussion of blocking pornographic content has offered no definition, no evidence, and suggested no technology. This is an affront to basic principles of the society, and while we acknowledge that this discussion is at a starting point, we feel that the way it is being conducted is harmful."
So not saying that porn should be easily accessed, but arguing that a centralised filter isn't the way to do it.
They repeatedly talk about the aim being right but the method (the technology) being wrong and potentially harmful.