What's the controversy about snail head?

The translation of this poem about why snails fight is as follows:

The original "five pairs of wine, second":

What happened to the snail's horn? I sent this body into the fire of stone. With the rich, with the poor, you are happy, but you are an idiot if you don't laugh.

Translation:

Living in the world is like being trapped in that little snail's horn. The space is so narrow. What's there to argue about? Life is short, just like a little light when stones collide, it is fleeting. No matter whether you are poor or rich in life, you should keep your eyes open, be happy and happy.

About the author:

Bai Juyi (772-846), a native of Xinzheng, Henan Province, was born in Taiyuan, Lotte, Xiangshan, and drunk. He was a great realistic poet in the Tang Dynasty and one of the three great poets in the Tang Dynasty. Bai Juyi and Yuan Zhen * * * advocated the new Yuefu movement, and together with Liu Yuxi, they called the world "Bai Yuan" and "Bai Liu".

Bai Juyi's poems have a wide range of themes, diverse forms and simple and popular language, and are known as "the poet's magic" and "the king of poets". Official to Hanlin bachelor, Zuo Zanshan doctor. In 846 AD, Bai Juyi died in Luoyang and was buried in Xiangshan. Up to now, there are Bai's "Changqing Collection", and the representative works include Song of Eternal Sorrow, Charcoal Man, Pipa Travel and so on.

Knowledge expansion:

Snails are mollusks of the family Snails, and there are more than 25,000 known species in the world. Snails have a soft body with a spiral shell outside, and the body is divided into head and feet; The head has two pairs of antennae, the back is 1 longer, the top of the antennae on the back has 1 pairs of eyes, and the mouth has a lower jaw and a toothed tongue shaped like a file, which is used for chewing and chopping food.

The abdomen foot is flat, and the bottom secretes mucus, which is convenient for the foot to slide on different surfaces through muscle contraction and breathe in tissues similar to the lungs for air to enter through the suction holes. Snails get their name because they have two horns on their heads when they crawl. There are many kinds of snails, distributed all over the world. Snails like to live in a dark, humid, loose and humus-rich environment, most afraid of direct sunlight and sensitive to environmental reactions.

The eyesight of the eyes is very poor, and only 6 cm away can be seen in weak light; Antennas have a keen sense of smell, and they rely on it to find food and mates. Snails mainly eat plant foods, especially vegetables, leaves and buds of fruit trees and roots and leaves of crops. Snails are hermaphroditic animals, but they cannot fertilize themselves. They usually mate in spring and autumn, and lay eggs after 1-2 months.