You're right, of course -- the 1917 Russian Revolution and the subsequent civil war involved atrocities on all sides that easily beat the French revolutionary terror.

On the other hand, it's standard to the point of cliché to regard the events in France post-1789 as specifically foreshadowing those in Russia post-1917 (with Lenin "correcting" some of Robespierre's mistakes, for instance making sure all the heirs of the old regime were dead).