Genocide is defined in Article 2 of the Convention on the Prevention and Punishment of the Crime of Genocide (1948) as "any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such: killing members of the group; causing serious bodily or mental harm to members of the group; deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part1 ; imposing measures intended to prevent births within the group; [and] forcibly transferring children of the group to another group."

If UN wants to change the definition, I'm all for it. At the time however, intention is a key requirement.

argue that it isn't because the intention isn't proven

They are full of shit.

Once the famine began, the authorities in Moscow kept getting notified about the food scarcity but continued to deny relief time and again. They were literally told "People are starving to death, do we have permission to provide air and reduce grain quotas?". Artificial barriers were introduced where people could not move between regions and into cities, thereby preventing people from searching for food elsewhere. Any mention of the famine was strictly forbidden and punishable by death.

Majority of the Historians do view it as a Genocide. A large number that don't cite the official definition as not being meat. It was an intentional crime, but not Genocide. The criticism from those that don't think it's a crime generally revolves around the argument "Crop yields were lower by natural conditions and therefore it's not intentional". They never address all the other factors listed above that prevented starving people from getting food.