Please read the last part of the narration.
” This cousin of yours, Mu’awiya, orders us to unjustly consume our wealth among ourselves and to kill one another, while Allah says:” O ye who believe, do not consume your wealth among yourselves unjustly, unless it be trade based on mutual agreement, and do not kill yourselves. Verily, God is Merciful to you” (iv. 29). The narrator says that (hearing this) Abdullah b. ‘Amr b. al-As kept quiet for a while and then said: Obey him in so far as he is obedient to God; and diqobey him in matters involving disobedience to God.
It is hard to understand the theory of our Sunni fellows that all the Companions are righteoues and stars, follow anyone you will be guided!