The armed robber might be charged too but if you shoot an armed robber and your bullet goes through the armed robber and kills an innocent bystander behind him you will be tried for shooting the innocent bystander. You must not take the shot if anyone is behind your target. So it is still Ukraine's fault for not firing their interceptor missile in a safe direction.

Ukraine needs to make peace with Russia and give up the parts of Ukraine that voted to join Russia before Russia defeats all of Ukraine or starts WWWIII.