I can certainly imagine this to be true. In the absence of knowing who they are, one can possibly guess without undue fear of being wrong.
On the patriarch’s side of it, there are surely Russian ultra-nationalist/ethnicist/caesaropapists who would just as soon see the patriarch dead as for him to depart even slightly from the "ROC=Russian identity=Russian imperialism formulation.
On the Pope’s side of it, one can imagine some of the modernists in the Church opposing the Pope’s meeting with a “moral reactionary”, which I would not doubt is the way they see Kirill.
It’s troubling to think about.