Not "You must kill unbelievers in Mecca," but you can, you are allowed to, but only after a grace period is over and only if there's no other pact in place and only if they try to stop you getting to the Kaaba, and only if they attack you first.
不是说，你一定要杀死麦迦城的异教徒， 而是说，你可以，你被允许这么做， 但只有等到宽限期结束之后， 只有当没有其他条约存在的时候， 只有当他们企图阻止你到达克尔白天房， 只有当他们先攻击你。