Justin, the way you pose this problem is symptomatic of the idealism on the US left that tends to see other countries as embodiments of ideological positions rather than institutions following their own historical trajectories. This anti-historical materialism of the US left is what drives me nuts.
Stalinism, or for that matter any form of the political system, is not that can be created or taken away by the fiat of a leader figure. It is an outcome of social-economic instituions that exist in a particular place and particular time.
If you consider what Russia was before the revolution - an extremely fargemented, underpopulated, backward collection of fedual fiefdoms, illiterate peasants treated worse than animals, lacking even most rudimentary civic institutions (such as local self-governnance, guilds etc. that developed in Western Europe), the already weak state virtually destroyed by the 1st World War, and the goal to be achieved - creating a modern industrialized urban society and a unified country capable of defending itself against Western European and US imperialism - there should be little doubt that there would be a LOT of power struggle, and a bloody one on the top of it, to achieve that goal - no matter who became the leader in 1917 or what particular ideology he espoused.
In short, Russia took its own road to development that was much different from that taken by Western Europe beacuse its social historical conditions were much different. The goal was to to build a strong industrial state - and everything else, form ideology to perosnal styles of th eleaders were merely a "superstructure" to legitimate that goal. They were neither voluntary (product of "personality cult") nor accidental, but the product of Russia's social, institutional and cultural history.
We need to look at Russia - and any other country - as aproduct of those institutional histories, and not embodiments of this or that utopia or a nighmare - as idealists on the left, right, and center claim.