Imagine for a moment that what is heard on the TV via the news is accepted as truth. For years the TV has been telling people that the sky is Red and since the TV has been accepted as truth everyone believes this and doesn’t question it. Then one day someone comes along and says “The sky is actually Blue, not Red! The TV has been lying to you, all you have to do is look up and see for yourself!”. The TV starts saying that this person is a liar and a bad person and that they shouldn’t be trusted or believed. They say that if you look up at the sky it will damage your vision and you'll never be able to see again.
In this scenario you’ve got 2 people that have been watching the TV and accept it as truthful, the sky is Red and the person saying its not can’t be believed. One day though one of these people decides to take a chance go ahead and look up and they see that the sky is really Blue and they didn't lose their vision! They now have seen with their own eyes that the TV isn’t telling the truth and that the person they called a liar and bad person was actually telling the truth. The TV continues to lambast the person that is claiming the sky is blue and all the people that listened to him and looked up to see the sky was Blue.
This person that has seen the truth then turns to the other person and says “Don’t believe what the TV is telling you, it has been lying to you and the person saying the sky is Blue is right! All you have to do is look up and see for yourself!”. However because of what the TV has been saying instead of listening to the first person and just looking up in the sky to see for themselves instead calls person 1 a “skyster” or a “skytard” and that they’ve been fooled by listening to the liar saying the sky is Blue. The TV continues to bring on scientists and experts that show studies and graphs claiming why the sky can’t be Blue and is in fact Red. They claim that people saying the sky is Blue have no evidence that it is, yet never look up to see the evidence that they are being told to look at.
Tensions start to rise between these two people because person 1 just wants person 2 to look up in the sky and see for themselves that it is actually Blue. Person 2 continues to refuse and believe the TV as it pours on more lies about the “skysters” and that there is no evidence to support their claims and they can't look for themselves because they will lose their vision.
As both sides continue to argue and try and get the other side to see the “truth” the division between them becomes deeper and deeper until they are left with 2 choices. One side either needs to concede and back down or they start fighting and whoever wins decides what is “true”.
The allegory of the cave, i.e. Plato's Cave, comes to mind...