Since when polluting valuable community information resource with paid commercial fluff became acceptable?

Aggressive promotion poisons the well for everybody. People come to HN for the honest information and opinion exchange with the like-minded, not to be bombarded with PR.

And by the way, I remember time when NH core were not get-rick-quick wannabes but engineers and, well, hackers. Which does not exclude being entrepreneurial. It just means being not easy for some 'smart business' to manipulate.

If the odds are worse without promotion, what rational human wouldn't use it?

The one that is familiar with game theory. Defection does work in the trusting, cooperative environment. First time. After that the community switches to 'tit-for-tat' strategy and bans the aggressor into oblivion. Or core of the community decamps to greener pastures leaving 'smart businesses' and their shills to their task of filling communal cesspit with more crap.