A deported rapist isn’t going to rape any of the natives and citizens anymore.
So if I understood you correctly, “natives and citizens” symbolises people in Germany in context.
Deporting unwanted behaviour doesn’t lessen its effect in both societies, which are likely connected in some way anyways (ie not North Korea). Rape is still bad for a society if it exists in other societies, because the non-prevention (not working on perpetrators/would-be perpetrators) and subsequent normalisation of rape harms everyone.
Deportation of unwanted behaviour is a bit like exporting toxic waste; don’t expect the poison not to come back in some way.
Ukraine doesn’t have the resources to start some weird revenge conquest, given that their allies fear MAD.