Notice the clunky transitions between Javascript and some degenerate form of C where everything is a member function of some hairy stateful singleton global object.
Oh, and all that matrix math isn't part of WebGL, the API neither provides graphics-specific utility functions nor general-purpose math operations. You have to roll it yourself in Javascript. You know, the way you have to write your own layout engine to write a 2d webpage?
This is all before we even get to the shader, where they just threw up their hands and said, "fuck it, let's have them send GLSL source as a wire protocol"
Also, security problems, weird device whitelist/blacklist, Microsoft's reasonable "hell no" stance, etc. Taking WebGL seriously is sucking the air out of the room and preventing progress on satisfying the demand for sane 3d on the web.
