Why the new player usualy play King's pawn oppening or Queen's pawn oppening?

Why?

Because they may have seen a couple of master games where masters played those moves.

Or they may have taken one of the introductory lessons here on Chess.com where they recommend those moves to new players.

https://www.chess.com/lessons/opening-principles

Central pawn or knight opening are strongest.

They both allow control of the center and rapid piece development, two important opening principles. King's pawn allows development of the light squared bishop and the queen, queen's pawn develops the dark squared bishop and it is guarded by the queen which makes it stronger. Moving a flank pawn in the opening doesn't really accomplish anything and it gives away the initiative. NF3 is also a good start, it allows the King's Indian attack or the Reti, but it requires more knowledge to play well. Moving one of the two central pawns is more intuitive.

When my Dad taught me to play at 5 yrs old. First opening was King pawn. For a long time I started every game that way.... I do lots of different ones now ; 50 yrs later. Lately I like Queens pawn.