Anytime people, especially a large group of people, believe that they know the absolute truth, they are dangerous. Add to that, they believe the truth comes from an absolute authority, the situation gets even more dangerous.
People can be made to do almost anything in the name of their absolute truth.
People can be made to do almost anything in the name of their absolute truth.
You'd believe if you just opened your heart" is a terrible argument for religion. It's basically saying, "If you bias yourself enough, you can convince yourself that this is true." If religion were true, people wouldn't need faith to believe it -- it would be supported by good evidence.