If the goals of a project conflict with the organization's business strategy, whose responsibility is it to identify these conflicts?

good question,

I think PMO should identify or program manager or top managers.

because maybe a project is defined but still  Project manager is not assigned, even in that stage such a this conflict should be identified.

Conflict is "a situation of competition in which the parties are aware of the incompatibility of potential future positions and in which each party wishes to occupy a position which is incompatible with the wishes of the other."  Conflict is viewed as a cycle: "As with any social process, there are causes; also, there is a core process, which has results or effects. These effects feed back to effect the causes." To understand conflict further, the situation must include elements of interdependence, emotions, perceptions, and behaviors.  For example, conflict occurs between parties whose tasks are interdependent, who are angry with each other, who perceive the other party as being at fault, and whose actions cause a business problem.