I'm just basically saying that I see no reason to give TOR exit points additional privileges over normal IP addresses. If your main defense against malicious accesses coming from a particular address is to block that address, and you decide that some addresses now cannot be blocked, well... now you've got a giant hole in your defense, right?

If a particular address is being used maliciously, it should be treated as any other address being used for malicious purposes. Treating some addresses as special would seem to defeat the purpose...