Remember Italy had almost as many land claims on France as on A-H.
And the only way people think A-H is joining Japan is if A-H actually declares war on Russia. A war between Italy and A-H will actually help Russia, as A-H will start pulling troops and reserves from their northern and eastern frontiers and shift them south towards Italy. This means Russia could draw down its strength in the Ukraine and Southern Poland move them elsewhere, if not to Siberia as the logistics did not allow a bigger army there.
Should France get the idea that joining Russia would get them the loving attentions of the RN they will dump Russia without hesitation.
And the only way people think A-H is joining Japan is if A-H actually declares war on Russia. A war between Italy and A-H will actually help Russia, as A-H will start pulling troops and reserves from their northern and eastern frontiers and shift them south towards Italy. This means Russia could draw down its strength in the Ukraine and Southern Poland move them elsewhere, if not to Siberia as the logistics did not allow a bigger army there.
Should France get the idea that joining Russia would get them the loving attentions of the RN they will dump Russia without hesitation.