Why didn't Bordiga/ the ICP never critique Lenin explicitly, unlike other communists like Rosa or Mattick?

Yes, I am aware of the obvious fact that, due to being a self-proclaimed leninist unlike Rosa or Mattick, Bordiga or the ICP as a whole wouldn't be so inclined to engage in open posthumous polemic with him. But, as we all know, the Sinistra Italiana hold views quite divergent from leninism, such as the opposition to participation in elections, opposition to nations' self-determination and defending organic, rather than democratic, centralism.

Anyways, Bordiga’s criticisms to Stalin to his face in 1926 may be considered an indirect criticism of Lenin, since the ComIntern’s centralization, Russian dictation of other parties' programs and way of discussing matters was the same since its founding afaik