If it was silly, a lot of altruistic people nevertheless fell for it.

For example, my impression at the time was that people thought that Google would be a responsible steward of Usenet archives:

https://en.wikipedia.org/wiki/Henry_Spencer#Preserving_Usene...

FWIW, it absolutely was believable to me at the time that another Internet person would do a company consistent with what I saw as the dominant (pre-gold-rush) Internet culture.

For example of a personality familiar to more people on HN, one might have trusted that Aaron Swartz was being genuine, if he said he wanted to do a company that wouldn't be evil.

(I had actually proposed a similar corporate rule to a prospective co-founder, at a time when Google might've still been hosted at Stanford. Though the co-founder was new to Internet, and didn't have the same thinking.)