I use the red X a lot. It means "disagree" if you press on it. It does not mean hate, or even dislike. I rarely use the dislike, thumbs down, because I will disagree with facts and opinions if they are wrong, but that doesn't mean I dislike the person.
It's too bad people don't read what those emoticons mean. And the heart one, I admit, is wrongly labeled. It's a good way of saying, I really like, it, or it is important. Instead, it is labeled as friendly. Very strange definition.
PS. I often get behind on threads, and so rather than answer every post, I just put the red X up. Esp. If it is something seriously heretical. I wouldn't want a newbie, or someone reading on the outside to think some glaringly wrong heresy wasn't opposed by anyone. There is so much bad theology in the BDF, sometimes I feel like the red X is the most important symbol in the whole pack. Again, disagreeing with the heresy, not disliking the person.