No, GTK+ is not the "real problem."

GTK+ has a very fine C++ binding, gtkmm. It even has a pretty nice java binding: java-gnome. People just really, really like GTK#, the Mono/C#/CLR binding.

The author even cites gnote, a C++ GTK app that uses gtkmm, as an example. He completely lost me at that point.

Example of what? His overall hypothesis seems to have been that GTK+ is so bad, people are driven to very high level languages like C#, and gnote sorta flies in the face of that.