Kassahun Molla Yilma, former head of Jimma University School of Law and prosecutor, argued in February 2021 that for the Mai Kadra massacre of the Tigray War and other atrocities taking place in Ethiopia, it would be in Ethiopia's interests to become party to the International Criminal Court (ICC). Among other reasons, Kassahun said that joining the ICC would "help catalyze reform regarding the legal framework regulating atrocity crimes in Ethiopia", since the provisions in the Ethiopian Criminal Code at the time "[did] not fit the nature of atrocity crimes committed [in] Ethiopia", and that the ICC would the Ethiopian justice system build capacity for investigations and prosecutions for the crimes. Kassahun said that as the ICC is a court of last resort, and since Ethiopia was not, as of February 2021, a party to the ICC, war crimes committed during the Tigray War would not be tried in the ICC.
https://en.wikipedia.org/wiki/War_crimes_in_the_Tigray_War
Kassahun said that the ICC is a court of last resort, and it would not try any war crimes committed in the Tigray war, because Ethiopia was not a member of the ICC and because the ICC is a court of last resort. Is there any legal reason why the ICC cannot do the same as it did against Russia?