I am not very receptive to those kinds of argument, arguing for widescale criminal/immoral acts today to justify a better future. Sounds very "Final Solution"-esque to me. And everytime this argument is used to justify an action in the present, it is much weaker as it presents merely a "possible" better future. However, you are applying an after the fact justification. There are many actions that justified themselves on the basis of a better future, but failed to deliver.