Why does the chrysanthemum in Huangzhou make Su Dongpo feel ashamed?

In Ming Dynasty, Feng Menglong's Book of Warning, there is an article "Wang Anshi's Three Difficulties and Su Shixiu", which tells a short story:

One day, Su Dongpo visited Wang Anshi and saw an unfinished chrysanthemum-chanting poem on Wang Anshi's desk. The first two sentences read: "Last night, the west wind crossed the garden, blowing yellow flowers and gold everywhere."

"West wind" is autumn wind and "yellow flower" is chrysanthemum. Su Dongpo thought: Chrysanthemum can deceive frost and snow, and flowers will wither and not fall. How can they be blown all over the floor by the autumn wind? The author must have taken it for granted. Therefore, regardless of Wang Anshi as his teacher and superior, he continued two sentences on the paper: "Autumn flowers are not as good as spring flowers, and he said that he should sing with the poet carefully."

Soon, Su Dongpo was demoted as "Ying Yong's deputy envoy" for the crime of "slandering the imperial court". In a blink of an eye, Chongyang has arrived. One day, the wind suddenly stopped. He invited his friends to enjoy chrysanthemums in the garden. As soon as he entered the garden, he saw many chrysanthemums withered by the wind and yellow petals scattered all over the floor. He suddenly felt ashamed.

Why did Su Dongpo feel ashamed? Obviously, it was the scene where the petals of chrysanthemum in Huangzhou were blown off by the wind, which made him realize the mistake of his view that "autumn flowers are not as good as spring flowers". Logically, this just involves the relationship between the four main nature judgments (also known as outspoken propositions).

Summary: In this short story, Su Dongpo's prejudice and the chrysanthemum in Huangzhou only represent a full-name negative proposition ("All chrysanthemums will not lose their petals") and a special affirmative proposition ("Some chrysanthemums will lose their petals"), which constitute a contradictory relationship in the "logical square".

Since Su Dongpo witnessed chrysanthemums falling petals because of the wind in Huangzhou, that is, the special affirmative proposition that "some chrysanthemums will fall petals" is true, then the contradictory negative proposition that "all chrysanthemums will not fall petals" certainly cannot be established. Su Dongpo clearly understands this logical relationship. He realized that he had made a mistake in continuing the poem, so he was ashamed and uneasy about his reckless behavior.