An authoritative opinion poll conducted an investigation into the causes of the 9/11 terrorist attacks around the world and found that 40% thought it was caused by the unfair foreign policy of the United States, 55% thought it was caused by the conflict between Islamic civilization and Western civilization, 23% thought it was caused by the evil nature of terrorists, and 19% did not express their opinions.
The most reasonable explanation for the above contradictory statements is that some respondents later changed their views.