> What exactly makes it hollow?
The fact that it is nonbinding resolution ritually offered every year, connected to no substantive action.
> Or do you call war crimes perpetrated in Afghanistan by the US and its allies a genocide too?
No, because “genocide” has a definition, and its not synonymous with the broader category of “war crimes”. Attempts to destroy a people as a people, as Russia is fairly overtly doing in Ukraine (accompanied by propaganda, as such efforts often are, denying that the identity sought to be destroyed is legitimate) is genocide. Other war crimes – which Russia is also committing Ukraine – are, well, other war crimes.