I am trying to convey the notion that with this line of thought, anyone could be doing anything because they are unreasonable or selfish. The original poster could be experimenting on us to mine text and find differing levels of consensus per time when HN faces controversy. I could be a bot trying to be more human. Without taking evidence into account, most of society is garbage.

Self-interest/motivation has its own MO. Also, sometimes motive isn't so important - physical behavior is. This is the evidence which can be collected. Otherwise you can't really assume much. Your original comment seemed to imply a conspiracy though through "built by".

This is a little detached from the original context though, and there's another issue there; People are not random processes, they may choose to pursue selfish strategies conditional on being in a system where it is uncritically "assume[d] people are being reasonable by default".