How to understand "stupidity is a moral defect"

I don't think so. Stupidity is sometimes a very subjective comment. What you think is stupid may not be felt by others. Maybe it's your feelings that show others a kind of stupidity. But, aside from this situation, let's talk about that kind of real stupidity.

Is stupidity innate or acquired?

It is rare in history, such as the Cultural Revolution. From the perspective of pure art, it is simply unparalleled. At present, the social ruling class is more intelligent. They use the desire of commodity economy to stimulate consumption, and more sophisticated technology to bind people and profitable materials together, make full use of their traditional customs, and extract the possible value of producers, so as to maintain their uncontrolled viral survival and reproduction.

Play dumb knowing it!

In our present life, there is often a kind of stupidity that is knowingly committed. They clearly know the above, but they stand on the side of reading slogans out of domestication instinct, fear, purposeful tolerance or completely part of the system. This stupidity is more terrible than before, because they can "smell" the enemy with great sensitivity.

Ignorance is a great evil.

Because moral judgment is a kind of value judgment, and every individual who makes moral judgment is the cornerstone of a person's value, that is to say, the value of the same person in the eyes of different people, that is, morality, is different. People who make moral judgments don't consider who you are, they care about what value you can produce.

Ignorance is not innocent. Ignorance is connivance to the evildoer. It is a group of ignorant people who drag down the civilization of the whole group. I can't forgive the ignorant, and I can't forgive the real fool.