That's just a intellectually lazy (or politically convenient) opt out. Anyway evidence is for the court which hasn't sat yet obviously, but you think there's not enough to issue a warrant even?
And the warrant is for Ukrainian children being forcibly deported, of which there is plenty of first hand testimony and NGO investigations showing that this has happened. To dismiss that all as 'impossible to judge the truth of' is incredibly fucked up, not a very good look being a denier of the forcible deportation and resettlement of children is it?