Silly article, written deliberately in an ivory-tower manner. Of course people manipulate others. Its the purpose of language. Of course the law allows it; its called salesmanship and is at the core of a free market.
That is why laws exist to protect the consumer from provider deception. The question, related to this topic, is just how manipulative are you able to be before you are being deceptive?
Manipulation is everywhere. Those that don't acknowledge it deserves being manipulated. You can't ignore such a huge part of all social interactions and expect that it will go away.
Next time I find a salesman on my doorstep, I'll have him arrested for attempting to hack into my brain :)