I think we are dealing with multiple meanings of word "communism" here.
Anarchists are opposed to communism in the commonly understood sense: a centralized state ruled by the communist party. Kropotkin was friendly with the Bolsheviks, who had not become communists in that sense yet. He supported the October Revolution, but he quickly became critical of Bolshevik rule afterwards. He believed it would not lead into communism in the sense the word was understood at that time: a society based on common ownership of the means of production without state or social classes.
Anarchists are opposed to communism in the commonly understood sense: a centralized state ruled by the communist party. Kropotkin was friendly with the Bolsheviks, who had not become communists in that sense yet. He supported the October Revolution, but he quickly became critical of Bolshevik rule afterwards. He believed it would not lead into communism in the sense the word was understood at that time: a society based on common ownership of the means of production without state or social classes.