So that argument is ok to protect the integrity of your SERPS, but people get all red in the face when it's used for safekeeping the nuclear launch codes?
I don't believe gp was talking about security by obscurity[1] and it would be wrong to frame it that way.
Instead, it's ranking and weighting by obscurity and it's a valid position to prevent gaming by bad actors. Statistical weighting is not the same topic as security such as closed-source cryptography.
Search engines heavily rely on obscurity to fight SEO and spam in general.