He does posit a contingency in accord with his disbelief in aliens. There are many who disbelieve. He then argues against that contingency, saying in so many words that, if there are aliens, they would not be included as necessary object for evangelism, much as it is for angels. I am not a disciple of Ken Ham, but understand him to lend authority to the biblical texts as the basis for his lines of thought. The source quoting him here should be considered an uncooperative, if not hostile, witness. The general subject is one that has so many people speculating in vain that it distracts from the simpler matter of being a good neighbor and trusting God for all that is good.
OK, agreed. The subtlety is an invitation to misinterpretation. And agreed that the discussion at best is a distraction from the thrust of the gospel.