We all try and use the wisdom and research of others to help substantiate our positions. The problem is many times those defending their position dont actually understand the intricacies of said "position" and therefor can not see just how poor the evidence they present actually is.
These types of people, especially once they get defensive, are nearly impossible to reach until their level of knowledge and understand grows and any evidence to the contrary presented against their views does little good because at the end of the day its just as unintelligible as their own "proof".
Only people who expand their understanding will truly be able argue a stance with any credibility and more often than not once they reach that level of understanding they quickly realize the flaws in their old beliefs and then actually alter their own beliefs to coincide with their new found understanding.
Anyone can scour the web or the library and dig up "data" to back their opinions but its not until they take the next step and actually read and understand both sides (or more in some cases) of the story do they actually "learn" and its this stage of the journey where the magic happens.