Why did Feng Weijian Tan and Feng Wei say that they were called "changing wind" and "changing elegance" by later generations?

There are quite a number of poems criticizing elegance and elegance, which reflect the social reality of heavy taxes, dark and decadent politics, numerous social abuses and poor people in the period of Li and Youwang. Poems such as "Feng Wei's Cutting Tan" and "Feng Wei's Explaining Shu" in the national style either satirize the rulers' insatiable greed or expose the rulers' shameless ugliness, which contains strong injustice in bitter satire. These works, which were called "changing the wind" and "changing elegance" by later generations, were the products of political decay and social darkness at that time.