As to why, the article states:
First, Russia seeks to influence Ukraine's March 2006 parliamentary elections by suggesting to Ukrainian voters that the current government in Kiev is economically incompetent and its pro-Western tilt harmful to consumers.
Second, the Kremlin seeks to discredit Ukraine's "Orange" government among Russian citizens in order to inoculate its population from the contagion of democratic revolution.
Third, Russia seeks to drive a wedge between Europe and Ukraine by painting the Kiev government as reckless and unreliable.
If this is what they're thinking, they are playing a game of high risk. Is it necessarily all that clear that the results they think will come about will in fact occur? Point the finger at Ukraine if things go south and expect the world to see Ukraine as the culprit. Not very smart.
One thing about Saudi Arabia they have been smart about is not to push the price of oil too high that it creates incentives to conserve or to seek alternatives. That is smart from a business point of view. But Russian natural resources are being used as political tools by an insular Kremlin that miscalculates chronically.
Here's one for you: Why would the Kremlin support Iran in the face of Iranian support for Chechen terrorists? Seems like the same kind of thinking. What look like short-term gains trump anything that might be had in the long run. But that is the Kremlin.