Can you explain in detail the cultural differences between countries reflected in this joke?

British police: Are the British fairer? (uncertain)

French chef: French food is very famous (but I recommend Chinese food).

Germans as mechanics: Germans have scientific spirit and are more rigorous in doing things.

Italians as lovers: Italians are more romantic and emotional.

Swiss as a manager: Switzerland is good at management, and the most famous hotel management education in the world seems to be in Switzerland.

Germans as police: it's terrible to get rid of Nazi countries.

British chef: It is said that English food is the most humble and unpalatable in the world.

French mechanic: Perception is greater than reason?

Italians as managers: sensibility is greater than rationality?