The key Leninist defence of the actions of the Bolsheviks in the Russian revolution is that they had no other choice.
The Kronstadt rebellion took place in the first weeks of March, 1921. Kronstadt was (and is) a naval fortress on an island in the Gulf of Finland. Traditionally, it has served as the base of the Russian Baltic Fleet and to guard the approaches to the city of St. Petersburg (which during the first world war was re-named Petrograd, then later Leningrad, and is now St. Petersburg again) thirty-five miles away.
The real limitations in Bolshevism can best be seen by the various oppositions to the mainstream of that party. That Bolshevik politics were not a suitable instrument for working class self-liberation can be seen by the limited way which opposition groups questioned Bolshevik orthodoxy -- even, in the case of the opposition to the rising Stalinist bureaucracy.
It is a truism of Leninism that Stalinism has nothing to do with the ideas of Bolshevism. Moreover, most are at pains to stress that these ideas have no relation to the actual practice of the Bolshevik Party after the October Revolution.
As is well known, the Russian Revolution failed. Rather than produce socialism, the Bolshevik revolution gave birth to an autocratic party dictatorship residing over a state capitalist economy. In turn, this regime gave rise to the horrors of Stalin's system.