There is a hidden tweak that allows changing the IP the immunization uses for the hosts file, see HostsBlockIP. This is no official setting that can be done from within the GUI since it's something important to very few and would confuse most others.
I've been familiar with that nice trick for a while now. I suppose you're probably right; having both options (127.0.0.1 and 0.0.0.0) would probably confuse many people.
Thanks for taking the time to say something about it.
I hope you include the Tools section on the final release, one of the major reasons I install Spybot on all my PC's. Its a no go for me if its not there in the 2.0 final release.