That's quite a judgment about the author, based on a single blog post.

You could argue that one reveals much more about their personality on a blog post that's about their though process, than one does when walking in a room and behaving during a wedding reception but... I'm actually not sure it's true, considered the former is the fruit of conscious reflection and the later is mostly not filtered by consciousness.

How would you explain when these predictions then turn out to be right? People who are this skilled at reading others are rare, but they do exist.

I'm sure they do exist, but I need to see harder evidence of these skills.

It's not enough that the person is correct in some predictions, they have to also make few mistakes. And the predictions must be objective and not vague or horoscope-like.

Would you be impressed if I made a prediction of a coin flip and was right? What about if I predict a 50/50 choice someone is about to make?

What if I have a book of instances where I made correct predictions?

Not impressive unless the mistakes are there too.