You misunderstand.
My beef is with NaCl, objects, Applets and ActiveX etc as well, mainly because they run outside of the browser's engine, sandbox, security model and conceptual model. you also have to ship them externally to the browser.
Canvas, video, webgl fine.
"Shumway is an HTML5 technology experiment that explores
building a faithful and efficient renderer for the SWF file
format without native code assistance."
But one security model is better than having two security models.
That's why e.g. the Unity3d plugin is so great. A complete 3D engine (with state of the art graphics, the ability to load almost any 3d format on earth, ...) does not belong into the browser. I don't want that code on my work PC.
OTOH, its great to have the ability to run games in the browser. The performance is much better than WebGL (because it contains compiled code, and because it is a complete, tuned, engine and not just an opengl implementation). And it's fairly safe, since it's built with Mono/.NET, you don't have problems with shellcode injection etc..