Why does Mr. Wehling target Leora Duncan and Dr. Hitz rather than the painter and the orderly?

Mr. Wehling targets Leora Duncan and Dr. Hitz because they are very vocal about supporting the killing of people to take the place of new people born, while the painter and the orderly are not. The two act nonchalant about death and killing innocent people as Mr. Wehling is struggling with the decision of whose lives he must take, so he figures he may as well kill them.