Why does it look like most people in this world are hostile to China?

Because China never wants the other country to fear her. As a result, most people can hate China without a tiny foreseeable consequence. Most people in the world are unsatisfied with their government and with their own situation; however, they fear their authority, fear the police of their government, so they redirect their grievance toward no-harmful China. It's like taking a painkiller without any cost.

Hating China has become an outlet of grievance for most people as China will not attack them because of their hate.

By the way, “most people in the world” is an over-exaggerated claim. “Most people brainwashed by the western media” is the proper assessment.