The FUD here is that the implication is that now text and images will be DRM'ed. EME only allows DRM'ing video and audio. Facts matter, and making stuff up to 'support' the point does not help. His post literally starts with "the fear is..." and then provides no facts to support it.
It may be so that they signed the death of the open web. But it seems to me that if this is your definition of the death of the open web, the open web has been dead since the broad support and use of the <object> or <embed> tags with RealPlayer, Flash and Silverlight - and very dead since broad adoption of EME before the W3C had any standards on it. Signing that death after all this time does not add anything except for some symbolism.