The author seems to want to frame Google's WebM move as a question of Good vs. Evil (as does Gruber btw.), which is not very helpful. As with most everything, there are both costs and benefits.

The main benefit is that Google's move may reduce the risk that the MPEG consortium goes crazy in the future, and starts to charge every possible user, causing havoc in the process.

The main cost is more certain: a huge inconvenience for content producers that were hoping to get away with going H.264 only, causing havoc in the process.

The interesting question is the usual one: is the benefit worth the cost?