The sorting system is broken because of gamification strategies that his son employed. It is an over saturated market on the supply side so they are making quality harder to discern. Voting rings are generally banned and enforced in many sites for this very reason, Eg. Stackoverflow. Source: I am a Stack Exchange moderator.
You argument then is his son isnt quite unethical because everybody getting noticed is engaged in a voting ring?
Google Argumentum Ad Populum. It is a logical fallacy.
I know you are trying to give the author the benefit of the doubt here, and thst is commendable, however I might suggest that reading his post a couple of times, the reason he might not have clarified this better from an ethical standpoint is that he likely has no ethical considerations when it comes to business, parenting and perhaps even life in general.