I dont know why "if they followed thier own standards, would be more likely to persist in beliefs irrationally." is presented as a counterfactual conditional. Even stubborn thinkers would stick to their initial ideas, not changing them later, then why is "following their own stadards" presented as counterfactual?
ex)People have their own standards for thinking, some of which encourage poor thinking. The heuristics that we use to form our beliefs is maintained by certain explicit beliefs about how thinking should be conducted- beliefs transmitted through the culture. People differ in their beliefs about how one should draw conclusions. Some think that changing one's mind is a sign of weakness and that a good thinker is one who is determined, committed, and steadfast. Such people, if they followed thier own standards, would be more likely to persist in beliefs irrationally. Other believe that good thinkers are open-minded, willing to listen to the other side, and flexible. Most of us probably agree somewhat to both of these beliefs. Whatever our beliefs, most of us desire to be good thinkers, so we try to follow our own standards.