That is because it is men who set the tone, so to speak. When they like something a lot, or they are very familiar with it, then they sometimes talk about it as if it was a woman. It is almost implicit that it is a man who is speaking, although women could speak this way if they wanted. It is not common to pretend that something is male, only female.

Male sailors talk about their ship as "she". Ships (other than war ships) often have a female name.

Same with cars, if it is a car that the man really likes. "Have you seen my 1962 Porche Boxter? Isn's she a beauty?"
I saw a war film where the soldiers referred to their tank as "she" and had a female name for it. The tank was practically their home, and their life depended on it.

Cities are sometimes also referred to as women, usually famous, beautiful cities - not ugly and unpleasant cities.

For example "Paris, that eternal city of love and youth.... "She lies snugly among the green fields of the central plateau, by the river Seine... Her beauty is known around the world...." (PS - there are no fields near Paris, I just made that up! )

I don't know why people refer to Seoul as "she" - apparently it's a very ugly and somewhat soulless city.