At first I doidn't understand why we call this sports activity table tennis before, why so. Why such a similar name to tennis?

I suddenly realized that's so easy, t it's very straightforward. The former is forplayed by two people to play a ball on a table, andwhile the latter is on the ground.

Some people say that people in the USA, don't treat table tennis as an athletic sport but as a game like snooker.

Table tennis is so populousar across China that nearlyeven the poorest schools have set up tables for table tennis.

"populous" = "has many people living in it". Used with words like "country, city, town, district, state."
Example: "New York is a populous city."

"popular" = "has many fans or players". Used with words like "singer, game, sport, movie, TV show."
Example: "Rihanna is a popular singer."

I don't understand why we decided to call this sports activity table tennis before, why. Why is the name so similar name to tennis?

This correction sounds more natural.

I suddenly realized that's so easy, t. The former is for two people to play with a ball on a table, and while the latter is played on the ground.

Some people say that people in the USA, don't treat table tennis as an athletic sport but as a game like snooker.

We treat it both ways here. :)

Table tennis is so populousar across China that nearly all the poorest schools have set up tables for table tennis.