Part of finding freedom is getting rid of natural tendency of associating with famous people. At a very small age we find out that success (Success Definition described in another posting) is everything and if you can't be successful at least you need to associate yourself with the successful. Success or associating yourself with the successful becomes the same thing. This molds itself into celebrity culture, this in turn then affects the issues you chose to support and oppose. If you think about any message or issue you support - Non Violence (Gandhi), Global Warming (Al Gore), Healthcare Reform (Obama), Gun Control (NRA) it automatically gets connected to a celebrity. Unconsciously or sometimes consciously the issue is relegated to the background and celebrity becomes the key issue. So all that message does is promote the celebrity not vice versa. If you need to discredit the message all you need to do is - discredit the celebrity (Kill the messenger). If you want to make a dent in global warming talk find out that Al Gore lives in a big house and has a big carbon footprint and suddenly the supporter of global warming is on the defensive. This you can see on a everyday basis. The politics of the world or discussions in a Birthday Party all follow this pattern - be quick to discredit the celebrity associated with the cause, cause dies on it's own. Find faults in Anna Hazare or his team to kill the Lokpal Bill. This is public display of how to oppose an idea by discrediting the messenger. This awareness makes us more aware of what is going on and keeping idea and advertiser of idea separate. It is like going into a store and saying it does not have good clothes because the mannequin in the store don't look real.
The second part to this idea of killing the messenger not the message is - internal. To evaluate any idea the first thing you need to do is kill the messenger. Once in your head the messenger is removed you can evaluate so much easily any issue you are presented. If you are dis-passionate about the celebrity then the message generally has not much of a 'bias' or 'drama' left with itself and it is a simple connection you need to make or reject. Even a fun dumb argument like pull shot is more attractive shot than straight drive or not, is a matter of simple choice. But if you now say Ponting played the best pull shot Vs Tendulkar played the best straight drive. Now all the emotions come to the fore and even if you never cared about one shot over the other, now you do!. This is the messenger effect - kill the messenger, not the message.