When politeness VS habit of ignorance

China is a country with an ancient civilization, but nowadays a lot of rude behaviour happens often in anywhere. It is caused by urbanization process; lots of people moved into city from countryside; they don't know how people behave in cities, and don't respect others. For example, they play mahjong in the elevator lobby of my building, and when they are playing they talk loudly and smoke. Once I asked them they're expected to follow good manners in public; they were exasperated and said that's their habit and right. In my country, people are supposed to be more polite. I thought this change in civilization in the country will last for a couple of decades. It depends on mainly people's education level.

Here is my revision of your short essay:

WHEN CHINESE PEOPLE FORGET TO BE POLITE

China is an ancient civilization that is grounded
on the Confucian principles of being polite and
courteous. Nowadays however, you will often notice
rude behavior in different parts of my country.

This cultural shift is due to the influx of people
from the countryside into the cities. Countryside
people are boorish and do not know how to blend
properly with city dwellers.

For example, countryside people play mahjong in the
elevator lobby of my building and when they do this
they talk loudly and sometimes smoke.

There was a time when I talked to a couple of countryside
folk and admonished them to be more mindful of other
people, but they said that they were habitual boors
and that they had every legal right to act that way.

Chinese people are supposed to be polite. This is part
of our culture and tradition. Unfortunately, many Chinese
are forgetting this important part of our heritage.
I guess, this is partly due to a lack of proper and/or
sometimes a good education.