They had to at least nominally have it, early on, to be able to hire the best Internet-savvy people.

Tech industry culture today is pretty much finance bro culture, plus a couple decades of domain-specific conditioning for abuse.

But at the time Google started, even the newly-arrived gold rush people didn't think like that.

And the more experienced people often had been brought up in altruistic Internet culture: they wanted to bring the goodness to everyone, and were aware of some abuse threats by extrapolating from non-Internet society.