I was just getting ready to say that I didn't think you could block "anonymous" or "private" or "blocked" callers, but apparently you can. That's cool.
Do keep in mind, though, should you choose to do something like that, that more than calls from more than one government entity show up as "blocked" or "anonymous", and blocking all calls would block those as well, should you have a reason to be in contact with them (if you know about it now). In this situation, I would consider it a fair trade-off.