Because smart people sometimes make very stupid decisions.
I mentioned the developer in the past the brought up a new RHEL server - on a public IP, enabled root login, and set the password to "redhat123" - right? TWICE.
Or the other one who wanted to share AWS credentials with a co-worker - so he posted them to a public github repo.
This default is amusing not because it's a bad choice, but because *nobody called them on it*. Stunning. If I actually used venmo I'd be annoyed.