Making someone a villain, is one of techniques to get trust of others.
Mr. Steve Jobs had advantage of this method. This book explains his excellent ability of presentation.
Amazon.com: The Presentation Secrets of Steve Jobs: How to Be Insanely Great in Front of Any Audience
Indeed, he always showed something made by another company as a villain when he presented his new product. Netbook against iPad, stylus pen against iPhone, and Sony VAIO against Mac Book Air. The audience are influenced by other products Mr. Jobs presented, And they are led to know advantage of products by Apple more impressively.
In political situation similar way is used frequently. Politicians often attack a certain group, such as a big company, an association, or even other countries. When we hate them, we are to be fascinated to the politician who blames them. It is psychological effect of cognitive harmony.
However this technique is very dangerous I think.
To blame something is negative behavior. An alliance against evil sometimes possesses great power. But when the evil is extinguished, the alliance will collapse. Or they would seek another foe. It is silly that seeking foe has changed into the final destination.
You have to be careful when you respect others. If the man attacks another one, I recommend you to doubt your emotion. Perhaps your trust is not true, but reflection of negative emotion to created foe.