https://www.folklore.org/Signing_Party.html
So no "of course" about it.
Note also that Microsoft had a "no easter eggs" policy starting in the early 2000s. It's not really a Jobs thing.
Note that this was in the aftermath of a summer with multiple major XP security issues.
It seems kinda harsh but it's important to remember the context: at the time, the security situation in Windows and Office was dire and it was (probably correctly) perceived as an existential threat to the company. I think "no Easter eggs" was as much for optics as for its actual effect on the codebase, a way to signal "we know about and stand behind every line of code that gets written; nothing is unaccounted for".