OOO is not speculative realism at all, rather it is a form of intuitive idealism.
1) not speculative but intuitive: the reliance on aesthetic intuition is dictated by the basic feature of « real » objects: they withdraw from all relations, and are thus inaccessible to thought.
2) not realism but idealism: any example of a « real » object is necessarily false, and gives us only an illusory « sensual » object. The scientific object is illusory, as is the humanistic object and the commonsense object.
For details see an analysis of Harman’s most explicit treatment of these themes in his « THE THIRD TABLE », here.