Limitations of theme poetry

You are confused. Foreign literature did not flourish in the period of Li Bai and Du Fu (about 900 years), but classical literature and romantic literature appeared after the Renaissance in Europe (13rd century), while pure love poems were romantic poets like Shelley Byron, and China was approaching at this time. Moreover, due to the deep suppression of human nature in feudal times, poets with love poems were naturally suppressed. After that, China experienced modern wars and could not communicate with western literature. It was not until the early 20th century that some China intellectuals spontaneously translated some foreign poems, and China's poems appeared as real lyric poets.