The accepted definition of genocide isn't what you think it is. It isn't what I thought it was either, until I educated myself.

I can't see any way to argue that blocking food to a large population of civilians is NOT genocidal. It doesn't require active military action to meet agreed UN criteria:

https://www.un.org/en/genocide-prevention/definition

Article II

In the present Convention, genocide means 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 part; Imposing measures intended to prevent births within the group; Forcibly transferring children of the group to another group.