That's a bit dishonest way to put it. The situation with extensions has vastly improved w.r.t. OpenGL. In the link you provided, it only needs to enable the ap

That's a bit dishonest way to put it. The situation with extensions has vastly improved w.r.t. OpenGL. In the link you provided, it only needs to enable the appropriate window system extension. It also prints out some info about other extensions but that is not required. It's a huge improvement that extensions need to be explicitly requested at init time. It's massively better than OpenGL, and API extensions can't be completely avoided in a multi-vendor cross-platform API without limiting to lowest common denominator.