"who I would like to call can not be inferred from the electrical activity on my scalp"
If I read the blog post correctly the claim is not passive mind reading. The claim is that the user has some training to issue the sorts of thought commands that can be reliably picked up. If I think "call mom" it doesn't do anything. But if I think "Up Up Down Down Left Right Left Right" maybe it can interpret that correctly as my preassigned shorthand for "call mom".