Postmodernism doesn't have to be right to be popular, and right now political power is a matter of popularity. Even if "the smartest people" prefer being right to being powerful, a dubious proposition if you ask me, that just means their less intelligent but more ambitious cousins will be the ones wielding the power instead.

The modern feminist and anti-racist movements have started to learn that their pet pseudo-science sociology is just not credible enough to counter anthropology biology and psychology; they see postmodernism as a way to hit back at "the scientific establishment" which they identify as aligned with their oppressors. At the same time, anti-corporate alternative medicine and animal rights activists (who travel in the same circles) have wanted to discredit the medical industry for decades and are turning to PoMo rhetoric as well. These groups are all at the vanguard of the modern left and all of them have a lot to gain by weakening science.

What's more, the ideals of reductionism and logic and the correct epistemology have been multiply, independently derived. China, India, and Greece all demonstrably converged upon them, and I'm sure many other unrecorded individuals have as well.

In the bastardized words of Tolstoy: "Good ideas are all alike; every bad idea is bad in its own way."

An ordered society, like Greece India and China, will tend to look and think very similarly even when direct communication is limited. Their traditions are the results of centuries or millenia of received knowledge which has had to pass the test of each new generation before it was transmitted to the next. In a sense you could say their memes are K-strategists; in a stable environment with limited opportunity to transmit themselves, the high cost of a more correct idea pays for itself by out-competing rivals in the long run.

In the modern world (more-or-less everything after the printing press), where the our technology made data transmission and storage trivial, the new environment put out new pressures. Old ideas were built to last but slow to spread; new ideas could easily afford to be much stupider and more dangerous as long as they reproduced and mutated quickly enough. These r-strategist memes are fads; they flood the field and by the time they've burned out there's a new one ready to go.

I don't think it's surprising that science is coming under attack; it is very expensive to produce a proper scientific mindset, while pseudoscientific fads can use aggressive mimicry to cheaply soak up any good reputation we generate.