Calling someone a "stalinist" is not much of an argument either. I think your argument suffers from a problem of attributing too many causes to a single most salient effect, such as an ideological proclamation, or the persona of the leader. In reality, historical processes are much more path dependent than ideologues, both bourgeois and revolutionary, want to admit.
Russia was am extremely backward country with a peculiar social structure characterized by the total absence of the "middle" or civil society as it is fashionable to say it today. This was quite aptly observed by Trotsky in _Results and Prospects_. (although Trotsky was too optimistic in his belief that the working class would fill that void - immaculate conception view of a modern society of a sort). Contrast that to Western Europe where the demise of feudalism in the 12th century allowed the ascent of the urban classes with its self-governing institutions (esp. guilds) which replaced feudal despotism. Russia simply had no such experience, so despite revolutionary proclamations, the post-revolutionary order was to a great extent path-dependent i.e. replicated the pre-revolutionary order with different personae.
So it makes little sense to attribute the rise of Stalin to the concept of planned economy, socialism, or for that matter the 1917 revolution. It is very likely that some sort of tyranny would emerge in Russia even if the Bolsheviks did not stage their coup after the "bourgeois" February revolution of 1917. The Bolsheviks supplied the tyrant, but not the tyranny.
In the same vein, it does not make much sense to blame Stalin for all evils that happened in the Soviet state. For one thing, his suppression of centrifugal tendencies can be seen as a positive force the every diverse Russian state with the history of "boyarschina."
It does not make sense to chastising people in different times and different places for not holding values that are dear to us. USSR was not a liberal democracy, but it is unreasonable to expect liberal democracy to flourish in a country with no previous experience of self-governance and democratic institutions. I think state socialism (which can be best thought of as an industrialization project with a human face) did a remarkable job in breaking away Soviet Russia (and other EE countries) from its path, Stalin and other tyrants notwithstanding.
wojtek