Yep the flaw is assuming that humans would actually select for constructive comments. It’s a case where humans claim that’s what they want, but human actions do not reflect this. We’d eventually build yet another ‘algorithm that picks what immediately appeals to most users’ rather than ‘constructive’. You’d also see the algorithm splinter along ideological lines as people tend to view even constructive comments from ideologies they disagree with unfavorably
I think it’s important to realize that almost everyone is at least occasionally a sucker. There’s a grift that targets basically every personality type. There’s grift for health conscious folks, for worried parents, for ‘I’m so much smarter than others’, for gamers, for outdoorsy types, there’s something for everyone. If you aren’t careful you’ll be laughing at the other ‘idiots’ while you yourself fall into a different trap.
Honestly once you start paying attention it’s really scary how many different and seemingly totally unrelated topics can be used to pull people into facism. So many times I’ve clicked on a different YouTube video or something and then all the sudden my feeds been taken over by right wing bullshit.