Why Chinese food so oily

1.The traditional diet is mainly rice and some leafy vegetables. Oils provide the fats needed for a more complete diet; The Chinese style was developed with the aim of reducing the calories of the fuel as much as possible. Oil added to a hot cooking container (wok or pan) helps to quickly transfer heat to all surfaces of the food; Oils and fats add a particularly pleasant texture to food and give off a taste in it. The tongue is sensitive to this pleasant "taste". Chefs sometimes finish a dish by sprinkling a few extra drops of hot oil on a plate.
2.Frying quickly in a hot wok means you can cook large amounts of food quickly without using too much fuel or requiring professional or utility equipment (such as an oven). This also helps save kitchen space and makes your kitchen more portable – you may just need a wok, meat cleaver, chopsticks. Oil is cheap. Very cheap. It can also be very tasty – seasonings can dissolve and suspend in oil more easily than other cooking liquids due to their viscosity – salad dressings come to mind. It's a cheap, quick win that coats your food with a strong flavor. The use of oil lubricates the food in the dish. This ensures that your food cooks evenly and that your wok doesn't wear out or damage. What you need is oil.

Wok-fried, pan-fried and deep fried dishes can all be oily. However, they do not have to be. Most recipes call for very little oil to be used, but it is easy to put in too much oil in order to keep the food from burning on the pan or wok. If you are cooking yourself, experiment with using less oil, but keep moving the food in the wok. If at a restaurant as the waiter to use less oil in the dish.

Not all chinese food is oily! Mostly just the fried foods. Nothing wrong with oil anyways unless you are counting calories. Plus most dishes are paired with rice which goes well with anything oily.

I think it depends on the regions in China.

That is only because the food you choose are oily.
Actually, one reason is a dish is not just for one person, and rice is your main food. Another reason is that they uaually use liquid plant oil. You can obviously see the mixture of water and oil on the surface, and you think oh it's too much oil. But compared to a crossiant, it is nothing.