Alas, it's true - people are not perfectly rational reasoning machines, because we aren't superintelligent with the ability to weigh every fact we've ever encountered at once. We rely on heuristics to get by.

But the imperviousness of obviously wrong beliefs in the face of what you consider rational evidence should not be taken as license to give up! Consider - if people tend to want to stick to their wrongness in the face of contradictory evidence, the wrongness still had to come from somewhere. All beliefs are caused by something, even if the cause would not meet a scientifically rigorous definition of "evidence". There's always logic in it, even if the logic isn't immediately apparent. For example, "Hard-code the beliefs of the people around you when young" and "Reject evidence that upends a large proportion of your worldview" are both highly logical heuristics that, incidentally, probably aren't nearly as likely to get you stuck in dysfunctional local attractors when attacking problems like "hungry tigers" as opposed to "gigascale global realpolitik".

All I'm saying is - don't be too cynical. At the end of the day, the truth still matters, and all we can do is keep plugging away at it. The wall is thick but not impenetrable, and we have come a long way already.