If we are not willing to commit ourselves to the vision of a rational and free world for all, humanity will suffer the miserable results. The problem is essentially the Second Law of Thermodynamics. Anything requires an input of energy to maintain or increase order. That requires many people taking an active role in influencing others to think rationally based on the evidence. An active role requires commitment, and commitment requires emotional involvement, and yes, even a passionate involvement.
Pessimism is self-defeating.
Instead, an aggressive vigilance and a committed, passionate, and constructive vision of humanity's future that recognizes our rational essence is urgently needed. To achieve our potential we must accept the organic nature of cultural evolution, and we must focus on our rational nature. We should not expect perfect societies and pristine progress.