what's the valid reason? all im seeing is him saying he doesnt want to get "bogged down" by describing things as they are. the un he claims is still working to define the word has basically declared it a genocide; if he wants to defer to an authority to deflect then he should probably choose a body that hasn't already made their stance on the subject pretty clear.

edit: i guess maybe you mean this?:

would alienate significant allies in the US, of which, she suggested, there were already too few, and provide opponents with an opportunity to shift the focus of the debate.

which is utter nonsense. if your allies are alienated by calling the genocide a genocide then they aren't going to be your allies in stopping the genocide they wont even admit exists.