The fact that you can build a browser which doesn't support DRM doesn't alter that fact that if we allow this in, W3C has officially sanctioned that the web, one bit and one platform at a time, can and shall be DRMed.
So sure. You can build a browser which only supports clear key. And that browser will not be a fully supported browser on this new encrypted and DRMed web. No FOSS-based platform will be a viable option to consume the web.
Now you can say that we have the same situation today, with Flash and Silverlight, so what's worse about this? Well: The fact that it has W3C's seal of "standard" approval written on it.
Congratulations: You just fragmented the WWW and to top it of you claim its a standard.
If we let this pass, in a year or two we will be having the same debate for <audio> and for <img> and for <script>. This is the beginning of the close-down on the web, and the only reasonable place to stop it, is at its root: No DRM, no EME and no CDMs in HTML5.
You can belittle those who disagree with you, saying they don't know what they are talking about. But it may just be that they are not so short-sighted about where this is heading as you seemingly are.
Right now Hollywood needs the web, more than the web needs Hollywood. Hollywood cannot afford not to be on this train. If we say "no DRM" enough times, they will come eventually. The music industry did. Everyone else did. Hollywood will.
Lets not sacrifice our open standards needlessly.