In that case it's bad to call someone childish because some of the best features of humans are only apparent for most people when they are children and not adults, but that isn't the point of what was said.

The point was that it is short-sighted of someone to say it would be evil if (say) Apple won the mobile war, but would be good if Google won the mobile war. Competition is a win-win situation for consumers, and a lack of competition only encourages stagnancy, which is one of the greatest evils of the creative world.