Why do all programmers start with Hello world as an example ?

Answer 1

Tradition

https://stackoverflow.com/questions/602237/where-does-hello-world-come-from

Answer 2

to give greeting to world before inter to the wonderful world languages😍

Answer 3

Hello world is like foo bar and spam eggs. In my opinion, it kinda filters personal input and reduces change of unwanted comments and reactions on code. Like when you do a scientific research, you don't input your own touch, but keeps it abstract.