I can see ignore overriding following of a tag. I do want people to own what they post and share however, so I don't want ignore to override that.
However, I do not want folks like tarekezombie ruining a tag for everyone. That doesn't make sense. I will make the change tomorrow. I plan on rolling out a pretty major update tomorrow, and I will add this functionality to that update.
Ignore will ignore the user, even if you follow the tag. So be it! :)