Since mohammed said to kill the infidel, how can islam be the religion of peace?

Muslims can claim Islam is the "religion of peace" simply for the fact that when the entire world has been converted to Islam (which is the true meaning of Islam, i.e. "submission") that there will then be peace. But there is Sunni and Shia Muslims and they kill more of each other than any modern religion, so they're pretty deluded when it comes to the meaning of the word "peace".