Many people advocate positive thinking as the solution to everything. They are all very wrong. Positive thinking creates more problems than it solves. You think positive, you fail to anticipate problems, you do stupid things.
Is negative thinking the solution? By no means. Negative thinking can be just as deluded as positive thinking. A negative thinker would portray anything good as yet another, sneakier way to do evil. A man may genuinely love a woman, and she would say that he is being nice to her because he is desperate or because he is trying to con her. A priest may genuinely be interested in one's spiritual salvation, and one would say that he is trying to steal his soul. I have known people who went from being positive thinkers to being negative thinkers. They did not become smarter as a result of that. They remained full of crap; all that changed was their attitude.
Right now, we are facing all sorts of major problems. Neither positive thinking nor negative thinking begin to be adequate solutions. Both cause more problems than they resolve. A positive thinker would say that focusing on such things is being negative, or being grandiose, or not taking personal responsibility. A negative thinker would say that these problems are too much for us to solve. Both will be dead wrong.
This means that both positive thinking and negative thinking are problems rather than solutions. The first fails to acknowledge the problem, the second says that they are insolvable. The real solution is honestly facing the problems that we have and using whatever intellectual capacity we have to come up with and implement actual solutions.