Dmitry, if someone destroys your brain or alters it enough so that it is effectively the brain of a different person, that is indeed murder. Your future utility is lost, and this is bad. Forcing you to behave differently is not murder. It may be a crime (slavery) or it may not be (forcing you to not eat your children), but it is not murder.

Genocide (as I understand the term) is murder with the goal of eliminating an identifiable group. It is horrific because of the murder, not because the identifiable characteristics of the group disappear.

My understanding is that preventing babyeating will be done in such a way as to minimize harm done to adult babyeaters, and only if such harm is outweighed by the utility of saving babyeater children. It is vastly different than genocide; the goal is to prevent as much killing as possible, not eliminate the babyeating aliens.

Incidentally, my hypothetical "final solution" is actually a Pareto improvement: every Jew who converts does so because it increases his/her utility.