I think all of you guys are fixating on one part of this question: Can I put users on an ignore list, and they not be able to see my posts or threads?

But there is a second part of this that I believe would also be really effective and is not at all unreasonable!: Can I put users on an ignore list, and not expect to see their posts or threads pop up, or see their posts in quoted text?

because right now, I can still see them post. All I have to do is click "Show this post anyway" and it pops right up! This is treating the post as a spoiler. When I see that message, my eye is instantly drawn to it because I don't see it very often. I usually click on it. Sometimes I am disappointed that I did, other times it doesn't really matter. If it was a user voluntarily limiting the posts that they see, I don't see how that affects anyone else negatively. It would only affect the person who CHOOSES to ignore posts from certain users.

That is not unreasonable at all.