Or the German government could do what every other western nation is doing and treat infractions on a case-by-case basis, rather than instituting a filter which could easily be abused (and for that matter, has been in every nation that's tried it).

National web filters are batting a perfect 0, and Germany isn't a unique snowflake.

That aside, you present a false dilemma by saying that the alternative is "doing nothing." That's not true at all, and I've already explained why in my introduction.