The problem here is that blacklists are never 100% complete, new malicious systems pop up on the Internet faster then any static list can be updated.
Infected zombie systems are a fact of Internet life, there are workstations with technically ignorant users at the helm.. and servers that were setup eons ago that are no longer maintained.
Instead of trying to block all these evil people, make sure the software
you're utilizing is secure and up to date.
That is all, certainly others here will disagree.