The author ignores the most spectacular example of Russian support for Serbia: the support that cost Nicholas II his throne and Russia an enormous amount of land.
World War I started when Austria-Hungary attempted (justly by most accounts) to punish Serbia for an assassination. Russia, foolishly and needlessly, elected to support the Serbs and declare war on A-H. Germany then was obligated to declare war on Russia; and France, in turn - and with England in tow, to declare war on Germany.
Ultimately, Russia suffered the 70-year-blight of Communism plus land losses in at the treaty of Brest-Litovsk: 1/3 of Poland, the Baltic states, parts of Czechoslavakia (Russia "surrendered" to Germany before the Germans did so to the Allies).
"World War I started when Austria-Hungary attempted (justly by most accounts) to punish Serbia for an assassination."
At this moment, this point may be minor but I think we should correct these misconceptions when they come up. The position of Austria-Hungary in 1914 was similar to that of U.S./Nato in 1999. Both were looking for an excuse to disable a proud and spirited so they could have a free hand in the area.
Austria-Hungary presented Serbia with conditions it could not sign on to because A-H wanted a war with Serbia.
in 1999, U.S./Nato wrote out conditions at Rambouillet that Serbia could not possibly have signed on to because U.S/Nato wanted a war there also.