If you think about it, all communication is a form of persuasion. But there is quite clearly different shades of persuasion. You have subtle persuasion on the one hand, which are harmless acts. I mean for instance, imagine if I were to you ask you whether you would like an Ice cream. But you said no. Then I began to describe the Ice dream, in very vivid detail, telling you how creamy it would taste when it hit your lips, and how you would enjoy the feeling of ingesting it. You would be salivating at the mouth, right now, demanding I take you to the Ice cream Parlor, this very instant! And on the other hand you have malicious and malignant manipulation, where somebody might, for instance, play on the insecurities and fears of another - can you imagine it? Being caused a great deal of anxiety and suffering? Admittedly, knowing someone has a weakness for a creamy Vanilla Ice cream and using this knowledge is playing on a weakness, but it doesn't cause anxiety and suffering, infact it causes happiness and elation, and I happen to think any positive attitude that can be instilled into a person through persuasion should be actively encouraged, and any form of persuasion that causes harm, mental or physical, should be actively discouraged. Some people happen to be better at persuading more than others, so the responsibility lays upon their shoulders to use their talent ethically for good purposes as opposed to bad.
arrgh, proved your point