Why OpenGL ES is so hard?

Because it takes minimum 76 lines of code to produce even the least meaningful output - A straight line. (And that too, only after doing unfair hard coding of matrix values)

Gist

[Do not confuse OpenGL ES with OpenGL. It might be possible to write a shorter program to do this task in OpenGL, but in OpenGL ES you need to use shaders even for the shortest of programs]