If they go to the moderation queue, then those comments will never be seen by the public, only by you as the administrator as long as you have either moderation set for first-time commenters, or full moderation turned on.
There is no way to "ban" them from your site. It simply cannot be done. IP addresses are of no use. All they have to do is reboot their modems to get a different IP address, or they go down to Starbucks or to any wi-fi hotspot and they are coming from a different IP. Even email addresses can be faked as can usernames.
Sadly for some this is an extremely hot-button issue, and blogging about it is going to attract this type of thing. It is just how it is.
My final suggestion: forget blacklisting and just turn on full moderation and that way there is absolutely no chance any comments you do not want on the blog will show up. You will have to deal with reviewing them. That is your job as the administrator of the blog.