>>17758322 (OP)The deeper question is, who actually "gets to decide" what is or isn't a genocide.
The real answer is nobody really does decide that question. There is no objective and authoritative list of genocides to be found anywhere, people are always free to disagree with whatever anyone puts forward, and it's largely a buzzword that has been used by almost everyone for various different agendas at different times.
Now that we've settled that, the real question becomes, how has this term been used. What was its original purpose when it was first coined and how has it been used and picked up by others since then. For example, if the news media uses the term genocide enough times, does it become official? Do they have to describe something as a genocide a certain number of times for it to officially become one? What if the news media in one country always describes something as a genocide, but another country's media doesn't? Are they both right at the same time, or is only one right, or does it even matter.